AP Fluids Test Solutions

I have solutions to the test available by email request only. If you have questions about your tests these should answer them. I will not post them. If you request them you must agree not to print them and to destroy them after you have reviewed them.

Honors Review Package

http://h1.ripway.com/DrCherdack/Break%20Rev%20Pkg%2008-9.doc
Here is the package referred to in your schedule. Its longer than I would like to have assigned for the break, and many of you are already working on the alternate test and the corrections, so here's the deal:

1) Make sure you do your work and write your answers on separate sheets so you can turn in your work on the assignment but still keep the package to study from. I will post solutions Monday PM so the assignment must be turned in Monday to count

2) If you do it completely it will count as 5 homeworks toward your homework grade, but I will only increase the number of required homeworks by 2.

3)  Also, you will get 1/2 point of extra credit for every problem completed. 

4) The material covered here (not exactly the same questions) will appear on the review quiz.

5) The nuclear reaction rate sheets can wait until Wednesday

Points 2, 3 and 4 should provide plenty of incentive to do the review.

Happy New year

Note that this will take me a long time to grade so be patient.

Honors Nuclear Reaction Notes and Worksheet1

Here are important notes you must read carefully and the first worksheet

http://h1.ripway.com/DrCherdack/Reaction%20Rates.doc

http://h1.ripway.com/DrCherdack/Nuclear%20Reaction%20Rates%20WS%201.doc

TESTS!!!!

In order to keep you from forgetting all you learned up until Dec 23rd I would test you on Monday. However, since this will yield horrible results we will have quizzes in all classes on Tuesday. 

For AP it will cover all material up to, but not including fluids.

For Honors, it will cover:

 motion with acceleration in 1 and 2 dimensions; 

 electric forces and fields on charged particles, i.e. the Coulomb equation and forces and accelerations due to fields( F = QT x E and a = F/Mass); 

energy and work and relation to PE and KE in general (W = F dot delta x)net work in = delta PE + delta KE if W= O delta KE= - delta PE)....F dot delta x  means F delta x cos angle betw F and x.

electric potentials and how they relate to fields  ( delta V = - E dot delta x) and how they change energies of charged particles( delta KE = -QT delta V); 

collisions in 1 and 2 dimensions and conservation of momentum

definition of impulse ( J = F delta t) and how it changes momentum and relates to force and time. Be able to use these to find minimum  distance between two interacting particles

Staircase ( Power) Lab

Remember the three point to cover are the effect of elapsed time to accomplish the work on power, the effect of increased load on power, and the proportion of the power required for changing the KE from rest ( O KE) vs the proportion needed change the PE.  This last point should be calculated for each of the four runs.

See you all next Monday.

Honors 3 ( Period 9) Masses

FGolks,

Anthony B's mass is 73 kg and his backpack was an astonishing 18.6 kg.

Miriam's backpack was a much saner 14 lb.

Good Luck

All students

I hope all those celebrating Christmas had a good day with lots of gladness. I hope Hannukah day 4 was also a very good one. And to everyone, I hope their celebrations are filled with happiness and that you remember to show gratitude for your good fortune by helping others.

Honors Fusion Reactor Report

I have posted a report with Annexes ( European for Appendices) on the Honors Material page on my website. Its the last link on that page. Download it and go through it and find material for your group. You don't have to print it all - its pretty long.

Thermo group. Lets stick to either steam cycles or the helium cycle , your choice. You will need to learn about heat transfer, but we will focus on converting thermal ( microscopic) to mechanical ( macroscopic) energy.

Electric Power group. I will try to reform this group but don't count on it. So, in the mean time you must pursue you goal of designing a generator.

Heating group can focus on neutral beams with a sideline in current heating.

Plasma group you've got plenty of good stuff here. Focus on main issues, number of particles and how long they are confined, and the required current ( coulombs per second circulating around thetokakmak) in the plasma

Magnets group, there is a lot here but you must also find basic information about how electromagnets work.

AP Practice Free Response Questions

If you do not have the package of AP Free Response Questions, email me and I will get them to you.

Honors Collision Test

I am offering the following: Over the break take the opposite version of the test you took and I will count it as a 50 point test. Correct your test and get 25 extra credit points. You may not print out these tests you may view them on screen only.

http://h1.ripway.com/DrCherdack/HnrUnit5%20Mom%20Coll%208-09.doc

AP Fluids

I will publish a solution set to problems from the test. Do not print these, just view them on screen and make sure you understand them.

AP Unit 8 Thermodynamics

The moment you have all been waiting for..... This schedule will be reviewed and some of the problems may get revised so look for updates. Also email me if you were not in school Monday to pick up the AP Mechanics package. Also REDA the Notes on Thermodynamics (see link below). You can do the gas problems on the Rev Sheet on Fluids over the break or by Thursday 1/8 if you can resist the thrill that long.

http://h1.ripway.com/DrCherdack/APUnit8Thersched08-9.doc

http://h1.ripway.com/DrCherdack/Review%20Sheet%20on%20Fluids%20.doc


http://h1.ripway.com/DrCherdack/HeatandEnergyConversion.doc

http://h1.ripway.com/DrCherdack/NotesWorkandEnergyR3.doc


http://h1.ripway.com/DrCherdack/NotesonThermoR4.doc

http://h1.ripway.com/DrCherdack/unit%208%20problem%20sheet.doc

http://h1.ripway.com/DrCherdack/Unit%208%20extra%20problems.doc

All students

I am posting your grades on HAC today so you might want to leave town. Please remember that I only post grades for three categories and that HAC can't calculate your overall grade properly. If you are doing well in the categories you will get a good grade. If you are not doing well, try fixing it, by doing more work, getting help, or bringing in brownies.

Due to unwarranted optimism, I did not take all the files home last night, so your grades will reflect the best information I have at hand. (This is especially true for Honors Section 3-9 th period- you lucky devils) . The HAC categories will say as of last Sunday but almost all classes will reflect work handed in Tuesday or later. I'll also include latest test scores where I have them (again Section 3 Honors gets a break).

Make the best of your day off, get some rest, but also catch up on any missing work and do your next assignment. AP, look for you next schedule by 5 PM today.

Honors Schedule for Unit 6

We are plowing ahead in our investigation of the physics required for us to learn so we can design a fusion reactor. We will now look at the reactions in more detail and see what is required to make sufficient power.


http://h1.ripway.com/DrCherdack/HonorsUnit6%20NuclearReactSched08-9.doc

All Students

We have many opportunities to show kindness to others this time of year. Who we are and what, if anything, we are worth, is largely determined by what we do for others. Please take advantage on these ways to help others.

It would really great on Monday, when I ask who has contributed to one of these, if every hand went up. ...and remember, its never a good idea to disappoint a physics teacher.

The school provided a can drive and still has

1) bricks for habitat for humanity

2) packages for service personnel in Iraq and Afghanistan

3) RPO Toy drive.

All Students ( and the rest of you as well) Collisions

Momentum is conserved for all interactions elastic, partially elastic, totally inelastic, or even where energy is added, as in the case of fusion reactions or collisions with overinflated 400 kg women ( if you weren't there 9th period Tuesday you won't understand.... and its better that way).

Elastic simply means total KE before = Total KE after. Totally inelastic is often used to mean the objects stick together.

However sometimes we choose to divide the interacting objects into" the system" and the external world as a matter of convenience. In those cases the net impulse from the external forces produce a change in the total momentum of the system: delta psystem = Jnet from external sources. If a system consists of 2 objects what one loses, the other gains.

Remember direction matters backwards = - forwards and x and y must be treated separately.

Honors Problems and Solutions

a) The problem we started in class may help you study for the test. I have changed the numbers from the class example to make it more realistic

It began with a deuterium ( n,p) moving at 9 E6 m/s ( where E 6 means x 10 to the 6th) moving towards an He3 (2p,n). The He3 was moving toward the D at a speed such that the total momentum ( remember they are moving in opposite directions) was zero. Now find the velocity of the He3 and then the total KE before ( i.e. sum of KE of both particles). The fusion reaction adds an additional 3E-12 J to the KE. The fusion products that come out are a proton ( p) and a He4 (2p,2n). Find the total KE after and using the fact that total momentum is still zero find the speed of the p and the He4. mp = 1.67E-27 and mn is about the same.

b) Steam and turbine blade: The steam particle transfers 280 pods to the turbine and since it starts at 240 m/s and ends up at -40 m/s and has a mass of 1kg.

It also loses about 28000 J to the turbine blade since it s tarts with 28800 J of KE and ends with only 800 J.

c) Particle slowing down: force has x components -2E-9 N y component +1E-9 N or magnitude 2.24 at about 26 degrees above the negative x axis

d) sled total momentum is 630 N after being thrown off Anthony still has a velocity of 3 m/s forward and 195 pods of momentum. Now Ashli has 630 -195 = 435 pods and her
velocity = 435 /Mass = 435/40 = 10.875 m/s

Honors Correction

Note there is a typo in problem 3: the velocity after the collision is 0 in the x direction and 2x10 6 m/s in the y direction. Here is a link to the updated version.

http://h1.ripway.com/DrCherdack/HnrsCollMom3r1.doc

Honors Assignment

Do this one for tonight. Problem 3 should take some persistence but you can do it.

See next post. I removed the link to the worksheet with an error. The new one has better pictures too.

AP Assignments

Be prepared for Mechanics. Review Forces , Work Energy, Power, for Wednesday Section 4, Thursday Section3. Review Momentum and Circular Motion for Thursday Section 4 and Friday Section 3.

Unit 3 Extra problems Odd is due Wednesday for Section 4 and Thursday for Section 3.

http://h1.ripway.com/DrCherdack/unit_3_extraodds.doc

Unit 4 Extra problems Odd is due Thursday for Section4 and Friday for Section3.

http://h1.ripway.com/DrCherdack/unit%204%20Extra%20Problems%20OddA.doc

All Students Difference and Average etc.

Many of you still confuse delta v and vaverage. You must understand this now.

vaverage = delta x /delta t

delta t = delta x/ vaverage

if a is constant vaverage = (vf + vi)/2

delta v = vf MINUS vi

delta t = delta v/a
Also delta x does not ever = a delta t and delta t does not ever = delta x/a

Collisions

1) Many of you are still not using components correctly. In 2D problems conservation of momentum must be applied separately right from the beginning. You must put all the y components and only y momentum components in one equation and all the x equations in the other. YOU CANNOT write total momentum after at 30 degrees from the x axis= total momentum before at zero degree from the x axis (well you can write it but your equation will be untrue.)

Using one equation to find pdeuterium' and then multiplying it by cos theta will not give the right answer, especially since you don't know theta for the deuterium.

2) Many of you do not use the T-83 incorrectly: 10 to the - 11 is 1E-11 not 10E-11. The E has the "ten to the power of" built into it.

All Students Labs

Make sure your lab reports include vital data such as the mass of objects and the reference height such as h0 for the conservation of energy lab

Honors Collision Worksheet revised solns

Here are some scribbled solutions. I have not double checked them. Use them as guides to check yours. Yours should have been done neatly on separate sheets. [If you downloaded the unrevised solutions for workshhet 2 discard them]

http://h1.ripway.com/DrCherdack/CollisionWorksheet1sln.doc

http://h1.ripway.com/DrCherdack/Collision%20Worksheet%202SOLNSr1.doc

QUIZZES AP AND HONORS

AP Fluid Quiz will be Tuesday as scheduled for Section 4 and Wednesday for Section 3.

Honors Momentum and Collisions short quiz on Tuesday, longer quiz Thursday.

AP Section 4 ( Period 4)

Bring your jackets on Monday.... NO, we are not going to Brush's deli.

Honors Collision Worksheet 2

Here is the link for tonight's assignment


http://h1.ripway.com/DrCherdack/Collision%20Worksheet%202.doc

All students including Topics

1) All students should be bringing canned goods into their first period classes including my first period Topics class.

2) Please take note of the other drives going on. Most of us are so fortunate that being homeless, hungry, or even toyless (think of life without an ipod !!!) is almost beyond our conception. One way to express your gratitude for your good fortune is share it with others.

3) To those who have adopted 506 as a second place to donate food: Mr C's classes are murdering us - in terms of food brought in. If 506 is your main food drop off we've got to increase our efforts.

Topics In Physics

Some of you seem to believe that since this is an elective, homework is also elective. Please allow me to disabuse you of this misconception. Get the homework in.

Read through all the remainder of the relativity notes and start thinking of topics. You must have a topic by next Wednesday.

Honors Collision Worksheet 1

You can do this including #3. Read the notes carefully and don't quit!

http://h1.ripway.com/DrCherdack/Collision%20Worksheet%201.doc

AP Section 3

Section 3 turn your tests back in if you haven't done so already

Honors and AP labs

Because of the concert tonight:

AP Buoyancy lab, formal, due Monday both sections 3 and 4

Honors conservation of energy ( cylinder and photogate), formal, due Friday both sections 2 and 3

Honors ballistic pendulum ( sphere and catcher) informal but must show all equations in symbols and then with numbers, due Monday

AP Lab

This is the lab for this week. Please download, print, and read.

http://h1.ripway.com/DrCherdack/Archimedes%20Lab%2012-08.doc

Honors Labs

Here are lab sheets for this weeks labs

http://h1.ripway.com/DrCherdack/Lab%20on%20Del%20KE-Del%20PE12-08.doc

http://h1.ripway.com/DrCherdack/Ballistic%20Pend%20Lab12-08.doc

AP Extra credit.

Due Wednesday AP 4 Thursday AP 3. An object is 1 m high it is submerged in a barrel that is filled with a water ( density = 1000 kg/m3) for the bottom half and oil (density = 700 kg/m3) for the top half. A cube ( density = 900 kg/m3) 1 m on a side is placed in the barre and floats partly in water and partly in oil. What is the height of the top of the cube below the oil water interface? Alternatively, what fraction of the cube is in the water?

AP Gravity Equations

Everyone should be able to manipulate the equations relating force to mass of a satellite and central mass ( such as planet and sun or moon and planet) and those governing centripetal force so that any one missing quantity can be found. There should be no problem finding any quantity in these equations provided enough of the other quantities are given. Please remember that the M in Ma is for the object that is accelerating, not the object causing the acceleration.

AP Torque Lab

Better late than never ( or maybe not, you be the judge in this case). You should answer the questions in the torque lab packet. Don't worry about the triple beam if you can't remember or never knew how one works. Also, if you have case 5a data you have all the data you need for 5 b and 5c. If you have done case 6 I will count it towards extra credit, after all it is the gift giving season.

Honors Section 3 (Pd 9) Labs

In your Projectile Motion Lab: 

1) most of you stated the purpose as predicting where a marble would land. Think in broader terms: the purpose was to confirm the model and equations we use to describe projectile motion.

2) manuy of use deltas where they do not belong. It is vx or vx average that is found from deltax/delta t. It is not delta v you are finding it is simply vx.

Groups, Teams, and Seating Plans for Honors and AP

Here are the new groups (AP) and Teams (Honors).  I tried to accommodate your requests while making viable groups and teams. I may have downplayed your subject request to match you with the people you requested or vise versa. If there is something you can't live with, email me or see me after school.

P =plasma  H = heating  E= electric power   M = magnets  T = thermodynamics

http://h1.ripway.com/DrCherdack/Seating%20AP%20-3%2008-9R1.doc

http://h1.ripway.com/DrCherdack/Seating%20AP%20-4%2008-9r1.doc

http://h1.ripway.com/DrCherdack/Seating%20H-2%2008-9r1.doc

http://h1.ripway.com/DrCherdack/Seating%20H-3%2008-9r1.doc

Topics in Physics Assignment

For light from a moving forward ( approaching) source we get f =f' *sqrt[(1+v/c)/(1-v/c)]. What do you get for a backward moving ( receding) source?

Your assignment for Monday is to develop the Doppler shift for light when the light source is moving away from the detector. Show your derivation and answer and turn it in Monday. Use the same approach we used before, finding the time difference in the station frame from when the end of the light wave reaches a detector - when the beginning of the wave reaches the detector.  You can do this two ways. Keep the light source moving to the right and place the detector to the left or keep the detector to the right and have the light source move backward, to the left. Once you have this time or period T in station frame expressed in terms of the period in the light source frame, T' invert the ratio to get f in terms of f '.

AP Fluids (Unit 7) Schedule and Torque Notes

Once again, against my better judgment, we are going to do fluids before waves.

Here are the links and do read the notes. Quizzes are always possible. On the Review Sheet, you don't have to do the Gas Problems.... yet.

Also, here is the link to the Torque and Moment Notes


http://h1.ripway.com/DrCherdack/NotesonTorquerev12-30.doc

http://h1.ripway.com/DrCherdack/APUnit7Fluidsched-08-9.doc

http://h1.ripway.com/DrCherdack/NotesonFluidDynamics.doc

http://h1.ripway.com/DrCherdack/Unit7APProbSh-05R1.doc

http://h1.ripway.com/DrCherdack/ReviewSheetFluid06.doc

Another AP Correction

Apparently the answer to problem 9 listed on the Unit 6 extra problems should be about .16 Hz or .16 per sec. It seems like the value given is for omega not f. I may actually have made that change and forgotten to go back and change the question to angular frequency instead of rotations per second.

AP Torque Notes

Having trouble with ripway this morning so see web page AP materials. The latest link on the AP materials page has some good notes on torque. Read them


The link on the AP materials page is 

documents/4bd2aeb9-9ce9-4bec-b4cf-779da049fe0c/350583-308508/downloadFile.aspx

Why the system just doesn't give the file name as the link is beyond me at this time. For a few weeks they dropped the first letter of the file names and now this. Wonder what'll happen next.

AP Section 4 Staircase Labs

I realize that this lab was supposed to be an easy one, but in all labs you should show the equations you use in your discussions. Few of you did this. Also, you were meant to include KE in your calculations of power. Furthermore, while f dot distance is a definition of Work, it is almost always more instructive to use work causes change in  KE plus change in PE in complex situations such as this one. 

For these reasons, most of the labs were in the B range, and even that was generous.

However, in the spirit of making this a recreational lab, I will only count it if it helps your grade.

AP Solution Sheets and Labs

1) Dennis has pointed out that there is an error on the solution sheet for rotational motion. In the problem where the pivot for the plank is 1 m from the end of the 7 m plank and we are looking for M2, the torque due to the mass of the plank should be taken as clockwise, i.e. as acting on the same side of the pivot as M2g.

2) For the conservation of momentum lab many section 4 reports discuss how momentum appeared to increase after some of the collisions and how friction cannot explain this since there is a gain not a loss.  Examine these cases and see if  p' includes a negative term as cart 1 bounces back after the collision. Is it because this negative term is too low due to friction on cart 1 that the momentum appears to be higher after the collision? Let me know in class or by email what you find.

Honors Sect 2 ( Period 6) assignment

Complete the calculation of change in KE for the example from class. This problem is outlined below.

Tritium ( M = 3 mp) came into collision with vx = 1,000,000 m/s vy =0. Deuterium ( M = 2mp) was at rest initially. After collision Deuterium has velocity' of 500,000 m/s at 30 deg above x axis and Tritium had vx'= 711,000 m/s and vy' of 167,000 m/s. Find out the change in total KE from before to after collision.

AP Quiz Etc

1) For homework tonight, do the advanced study assignment from the lab as well as the odd extra problems

2) Due to delays in getting to torque and equilibrium, the quiz (it has to be called a quiz now) will be on Tuesday. We will begin to work on either fluids or waves over the weekend, keep checking here for the new schedule.

AP Unit 6 Extra problems

Sorry folks, here is the link for the extra problems

http://h1.ripway.com/DrCherdack/AP%20Unit%206%20Extra%20Problems.doc

AP Unit 6 Revised Assignment for Tonight and Solns

The schedule has some errors. Please do Problem Sheets R-1 and R-2 and the odd problems from the extra problems.

You may find these helpful:


http://h1.ripway.com/DrCherdack/APRotationalSlns0001.pdf

Food Drive Etc

Folks, as you know I don't have a real 1st period class. However, we will have a food drive in 506. Please bring canned goods in. If you bring them to your first period class that's fine. If you bring them to 506 place them in the box under the desk against the side white board.

All students Study Groups

I am open to requests for study groups. Since the groups should represent a balance of skills and personalities I will not necessarily honor requests, but I will consider them. E mail me with your requests.

AP Study Group Report

I heard enough whining to convince me to relent on the Unit 5 meeting and report for AP students. AP only start with unit 6

AP Centrpetal Lab corrections for Msg

Here is a link to discussion as to why you can ignore the correction for the fact that there is a vertical component of FT and how to calculate the true Fc and Mstopper omega sqrd r if you don't ignore it.

http://h1.ripway.com/DrCherdack/centrpetal%20correction.doc

Honors Unit 5 Schedule

Here is the new schedule and a problem for tonight. NOTE Assignment for this weekend is The Unit 5 Worksheet 1r1 not Prob Sheet. Momentum Worksheet M is for Monday night

Tonight's problem is:

1) For a totally elastic collision, use the equations we developed yesterday and today (see earlier post today) to find v1' and v2' given v1 = 1 m/s v2 = -1 m/s and m1 = 1 kg m2 =0.5 kg.

2) Do this again only use the masses and v1 and v2 from the last run ( row 12) of our momentum lab. See how far off your results are from the lab and see how much KE was lost during the real collision. use (MAv1sqrd/2 + MB v2 sqrd/2) - MBv2'sqrd/2 since v1' =0

http://h1.ripway.com/DrCherdack/HonorsUnit5Mom%20colsSched08-9.doc


http://h1.ripway.com/DrCherdack/MomentumWorksheetM.doc

http://h1.ripway.com/DrCherdack/Unit5Worksheet1r1.doc

http://h1.ripway.com/DrCherdack/Unit5HnrsProblemSheet.doc

Honors Elastic Collisions

As promised here is the derivation. Stay tuned for some problems in collisions and momentum.


http://h1.ripway.com/DrCherdack/ElatCollderiv.doc

All students including Topics in Physics

Study groups must meet at least once for one hour outside class per unit and every student must turn in a report covering where, when, who, and what was discussed. THIS IS A REQUIREMENT even for TOPICS.AP owes reports for Unit 5 and 6. Honors just for momentum and collisions.

Topics in Physics Problem

For the first problem you start with equations that describe the fact that the spherical light wave illuminates the surface of sphere ct meters in radius. Thus for every point on the sphere we have xsqrd+ysqrd +z sqrd = r sqrd and since the light wave moves outward ct meters per second the radius is ct. One equation describes the events seen in K the other in k. I asked you to demonstrate that the events seen in one frame are consistent with the measurements of those events in the other frame. So if someone in K sees point x y z get hit by the light wave at time t, someone in k will see the same event and describe it as happening at t', x', y' and z'. In other words show that if point t,x,y,z, complies with the equation in K, then its transform in k complies with the equation in k. One way to do this is to take the k equation and write the four quantities as the transformed quantities from K, (i.e. replace t' with the correct function of phi, gamma,t,v,x, , x' with the correct function of phi, gamma, t,v,x etc. using equations (6). Then simplify this equation to see if gets you back to the K equation.

Hints

1) divide through by phi sqrd since it appears in every term.

2) gather all the t terms on one side and all the x terms on the other.

3) factor out csqrd t sqrd from one parentheses on one side

4) factor out xsqrd

5) remember what gamma sqrd equals

REpeat of Spreadsheet for Honors Lab

Just in case you overlooked the revision:

Sorry, left out the link. Here is the latest spreadsheet. Try using it to find pbefore and pafter and make sure they match. Remember that the last two runs Cart B comes in with a negative v. Note that v1 and v1' are for cart A; v2 and v2' are for cart B.

Lab sheets turned in on Monday if pretty good will be worth 25 extra credit points. They will all be due by Wednesday so do give it a shot.

Have a very Happy Thanksgiving and do think about all you have to be thankful for and about physics ( although that is redundant since physics is one of things you should be thankful for, after all, try cooking a turkey without heat transfer)

http://h1.ripway.com/DrCherdack/Hon3Mom%20lab-1.xls

Spreadsheet for Honors lab

Sorry, left out the link. Here is the latest spreadsheet. Try using it to find pbefore and pafter and make sure they match. Remember that the last two runs Cart B comes in with a negative v. Note that v1 and v1' are for cart A; v2 and v2' are for cart B.

Lab sheets turned in on Monday if pretty good will be worth 25 extra credit points. They will all be due by Wednesday so do give it a shot.

Have a very Happy Thanksgiving and do think about all you have to be thankful for and about physics ( although that is redundant since physics is one of things you should be thankful for, after all, try cooking a turkey without heat transfer)

http://h1.ripway.com/DrCherdack/Hon3Mom%20lab-1.xls

AP Lab

Due to popular demand ( really do to the lamentable lack of competence when it comes to swinging stopper over your heads) we will continue the lab on Monday. On the other hand you better be able to derive the relationship between omega and M1 for orbital motion. Just set M2 vsqrd/r = FG where FG = G M1M2/r sqrd. and G= 2/3 E-10

Enjoy your Thanksgiving and remember how much you have to be thankful for ( like physics, after all just try living without it).

Honors Homework

I guess you can't teach an old dog new tricks. I left the height of the vacuum chamber out of problem 3 again. The height is 1m. Use this to find the field. The use that field, tec to find how far the nucleus rise during its .5m of horizontal travel. Let me know if it hits the top befoer reaching the end.

Honors Homework

About the review sheet homework:Tonight do the first 6 questions and the first problem. Complete the sheet for Monday. In all cases place answers on clean homework sheets. Answers should show work as needed and answer in sentences such as the horizontal distance traveled by the cannonball is 22500m. You keep the questions and answers sheets.

Honors Momentum Lab Data

Here is the data that might make sense. Your job is to use this data to demonstrate that
p before = p after. You need to figure out which times to use for which velocities.

Look at the masses to figure out whether cart A bounced back off cart B or continued moving forward.

Note for the last two cases cart B was moving as well as cart A before the collision. For these cases you are better off comparing Delta pA with Delta pB . They should be equal but opposite. Make sure you get the signs right for these runs in particular vA and vb are opposite.

http://h1.ripway.com/DrCherdack/Hon3Mom%20lab.xls

AP Centripetal Force Lab

Here is the Lab Sect 4 did today and Sect 3 will do tomorrow

http://h1.ripway.com/DrCherdack/CentripetalForce08-9.doc

AP Test on Unit 5

On some of your answer sheets I placed a (-) sign in front of the impulse on the probe. This is is NOT correct during grading some versions I thought the question was the impulse on the main capsule which would have been negative but the question on all versions was impulse on the probe which is positive.

Topics in Physics

Your assignment for Monday 12/1 is

1) do the exercise on page 11 of the notes, i.e. show that equation 7 transformed using equations 6 yields equation 8

2) Using the final transforms on page 12 demonstrate that

c squared tau squared is the same in all frames where
c squared tau squared= csquared tsquared - xsquared-ysquared-zsquared

This looks a lot better when you write correctly.

Enjoy your holiday, but never quit doing and thinking physics.

AP Schedule Change More Links for Rotational Motion

Here are more links.

1) Add Problem Sheet r-3 to your assignment due Monday 12/1

2) Note that the links Problem Sheet R-1 and R-2 are for the the items that are called WS R-1 and WS R-2 on your schedule.

http://h1.ripway.com/DrCherdack/RotMotionDefseetc-07.doc

http://h1.ripway.com/DrCherdack/ProblemSheetR-3.doc

http://h1.ripway.com/DrCherdack/ProblemSheetR-1rev1.doc


http://h1.ripway.com/DrCherdack/ProblemSheetR-2.doc

AP Links

Here are some more of the links for Unit 6

http://h1.ripway.com/DrCherdack/APUnit6ProblemSheet.doc

http://h1.ripway.com/DrCherdack/PlanetWS.xls

Notes on Momentum

:
http://h1.ripway.com/DrCherdack/Notes%20on%20Momentum.doc

AP Lab Part 2 Revision

Apparently errors were made in recording the data on this run so please see the revised sheet.

Only the first two trials on this sheet can be used.

http://h1.ripway.com/DrCherdack/AP4%20momentumlab2.xls

AP Schedule, Lab etc

1) Your crash lab is due Monday. Its formal

2)Here's your schedule and some links. Rest are coming. Make sure you do the reading by Monday before class.

http://h1.ripway.com/DrCherdack/AP%20Unit6sched%2008-9.doc

http://h1.ripway.com/DrCherdack/Rotational%20Dynamics%20Eqs.doc

http://h1.ripway.com/DrCherdack/Rotational%20Dynamics%20Eqs.doc

AP Unit 6

There will be a folder in the folder rack with an assortment of sheets for thisunit in the rack. Most of this stuff will be posted but if you want grab some stuff rather than download it, here is your chance. First come first served, one copy per person.

AP Momentum Lab 2

Here is the link for our latest triumphs. Incorporate this new data into your labs as an addition, not a replacement, for the other runs.


http://h1.ripway.com/DrCherdack/AP4%20momentumlab2.xls

All Students Study Groups

As of the next unit a one hour meeting of your group outside class per unit is required. Each student must prepare a report consisting of four or five sentences saying where, when, who was there and what was studied.

AP Assignment

Since you folks are all so intelligent. Here is a tough one to do tonight.

A rocket is launched vertically from the ground with an initial velocity of 0. The rocket motor produces a constant force for 5 seconds and then burns out. The rocket has a mass of 0.5kg and reaches a maximum height 0f 150 m ( that includes coasting). What is the impulse delivered by the rocket motor. ( Don't forget gravity operates during the first 5 seconds)

AP Momentum labs

Here are the spreadsheets for the momentum labs for Sections 3 and 4. Download the sheet for your class and test each run for momentum and energy conservation. The momentum conservation should be pretty good with just some slight losses to friction. Energy conservation should be another matter due to losses to crinkling tape, smashing velcro, creating noise , etc. Since I did not get the links up until this morning the labs will be due on Friday.

This lab requires a formal writeup.


http://h1.ripway.com/DrCherdack/Momentum%20lab%20A3.xls

http://h1.ripway.com/DrCherdack/Momentum%20lab%20A4.xls

Blog Downloads

It seems that some down loads are occurring but the file storage site is still seeing more traffic than is actually occurring. If you have used or do use the download feature on the blog, email me with what you tried to do, exactly when,  and what actually happened. Someone may have a virus or corruption that is causing the problem.

Documents and Links

My webpage on off course will not let me upload documents. I am waiting for advice from our tech people on that and for info from my other file storage site as to why they think 135 KB of download exceeds a 150 MB limit.

Stay tuned as I try to work out the latest folds and wrinkles in cyberspace.

Topics in Phyiscs

Read through the notes up to equation 7. Be prepared, you will have an assignment for Thursday.

Computer Graphics Type

Out Techxplore team is in need of some one with expertise in computer graphics. Join our team as we try to create a solution to  an important problem in  modern life (no, not how to get instant updates on paris Hilton's latest exploits) and then build a great presentation. Send me an email or stop by 506 ASAP if you are interested

Links

My file hosting site is having problems. Check my website AP and Honors Materials pages, I will try to upload files there.

AP Assignment

For homework this weekend do the colliding pendulums problem with m2 = .5m1 and then for m2 = 4 m1

Honors Assignments

Since we are running a bit behind our pretty ambitious schedule, we will be spending more time on 2 D forces and motion basics. I'll give you until Monday to complete the assignments to date. By Tuesday we should have completed projectile motion (motion in a field) and start to discuss momentum and collisions. We should have another, more quantitative 2D quiz on Thursday. Stay tuned for more details.

AP Momentum Solutions

Get em while they're hot. Fresh back from a sojourn in cyberspace solutions to selected Unit 5 problems

http://h1.ripway.com/DrCherdack/AP%20Unit%205%20Solns0001.pdf

Topics in Physics

Here is the material on Relativity. Download it and print out the and read the first five pages by Thursday.

http://h1.ripway.com/DrCherdack/NotesonSpecialrel15.doc

Honors Projectile Lab

We will try to get to this lab this week. Look it over.

http://h1.ripway.com/DrCherdack/hole%20in%201lab%20rvwd10-08.doc

RM WS Link

Try this. I don't know why the other doesn't work. Got corrupted somehow.


http://h1.ripway.com/DrCherdack/Relative%20Mot%20WS%20RM10-08.doc

AP Elastic Collisions

Review this derivation before class Tuesday


http://h1.ripway.com/DrCherdack/ElatCollderiv.doc

All students The force of gravity

There will be a quiz tomorrow and any student who tells me the force of gravity = 10 N or 9.8N or is the same on all objects will receive a failing grade.

All Students Homework

We are tired of trying to guess what homwork assignment we are looking at. All homework must clearly identify the assignment if it is to be recorded. It should give page number or chapt number if end of the chapt problem ( about the only kind of text problem for AP). If a problem sheet or worksheet, it should give sheet name and number where appropriate and problem numbers

AP Unit 5 Schedule Etc

Here are the materials for Unit 5 on Momentum and Collisions

http://h1.ripway.com/DrCherdack/APUnit5MomentumSched08-9.doc

http://h1.ripway.com/DrCherdack/Unit5Worksheet1r1.doc

http://h1.ripway.com/DrCherdack/Unit5Worksheet2r1.doc

http://h1.ripway.com/DrCherdack/Unit5ProblemSheet.doc

http://h1.ripway.com/DrCherdack/Unit5extraproblemsr1.doc

Honors Sect 2 ( 6th period)

My homework records for this class show lots of blanks. Your home work grades may be lowered dramatically from current HAC. My records show about 42 assignments and most of you have turned in about 20-30. I find this hard to believe. Please do me the following favor. Gather all your home works in chronological (by date) order, clip them together as best you can and bring them in tomorrow. This will ruin my weekend, but its for your sake that I need to get this settled.

AP Solutions

Here are some solutions. I wrote these a while ago and haven't checked these lately. Hope they help.

http://h1.ripway.com/DrCherdack/WorkandEnergyWS-Asln.doc


http://h1.ripway.com/DrCherdack/PowerandEfficiencySlns.doc

AP Worksheets

This is your homework for the next two nights. The sooner you do it the sooner you'll know what you need to go over before the quiz Wednesday. The second sheet is really easy.

http://h1.ripway.com/DrCherdack/EnergyandWorkWorksheet1a.doc

http://h1.ripway.com/DrCherdack/PowerandEfficiencyWorksheet.doc

AP Assignment due Monday

We are moving up the schedule a bit. DO the problem sheet for class Monday so we can go over all the potential problems for the unit before the test.

Honors Sect 2 (Period 6)

Everyone, please turn in your Static Electricity Labs. Also, if you were one of the 9 who got your a=F/M lab back last Monday turn that back in too. The system failed to save them when I entered them last Monday. No fooling around with the grade guys.

All Honors

Monday and Tuesday we will do a lab I usually reserve for APs but it does make the idea of components of forces really clear and you should get really good results.

Please down load it and look it over carefully. We will do it for one position only not three and it will be a height of about 70 cm. If we get it done quickly enough we will then get to do a lab for projectile motion which most students have fun doing.

Components Lab
http://h1.ripway.com/DrCherdack/normal%20perp%20labwphotgatesR2.doc

Projectile Motion Lab

http://h1.ripway.com/DrCherdack/hole%20in%201lab%20rvwd10-08.doc

Honors Section 3 ( Period 9)

Be prepared to redo the electrostatics lab on Monday and to do it quickly.

Last Call Honors Period 6 Last week's test

Please turn in your tests from last week tomorrow. I may have adjust your grade upward. I can't do it unless I have your test.

Real AP LAb Link

Since the a=F/M lab was a nightmare to grade I certainly don't mean for you to do it again.

Here is the correct link

http://h1.ripway.com/DrCherdack/Lab%20on%20Delta%20PE%20mv22gate.doc

AP Labs

1) Save your labs because colleges might want to review them before granting credit.

2) You'll love this one . We'll do it Wednesday and Friday.

http://h1.ripway.com/DrCherdack/Lab%20on%20a%20=F%20divided%20bym%20AP.doc

Lab Reports

I am operating under the increasingly difficult to maintain supposition that you don't do this just to drive me nuts.  That it really is due to your lack of facility with graphs, not perverse senses of humor.

I have just gone through 9 resubmittals of the a=F/M labs. Lots of errors were cleared up, but SIX of them still failed to compare the numerical value of the slope for the 100 g series to .98N or the slope for the 50 gram series to .49N. Several did make reference to individual points and how they showed a/(1/M) was close to F, some did mention that the acceleration did decrease as Mcart went up, some did calculate the slope somewhere, but you all mentioned that the slope should equal the force and then  6 of you failed to find out if it did. Some scientists you are; weren't you even curious?

The reason for using the slope is because a best fit line represents data from several trials so  this best fit line, which averages out random errors of individual runs, tends to give more indicative results. Also using the slope can remove some constant systematic errors like those caused by friction in the pulley.

In any case I believe I told most of you what you should do in my comments or orally, so next time make sure your read the relevant notes, try to remember what I tell you and check the blog posts as well.

AP and Honors Students

Try going to my OnCourse website and go to the Honors Material page and look over Notes on Energy Fundamental. A good review for honors and not a bad overview for AP.

Honors Unit 4 Schedule

If you downloaded the Unit 4 Schedule before 10:25 this morning you got the wrong version. Please download it again.

Also the link to the RM worksheet is not working, I'll fix it before you need it.

Honors Unit 4 Schedule

Here is the schedule for a unit where we will study motion in 2 dimensions and also review electric force and energy. Note we will have a second test on electric force and energy on Thursday.

Here is the problem mentioned in the schedule as due tomorrow:

Find the potential energy when a deuterium (D) nucleus ( one p and one n) is at a distance of 5x10-15 m from tritium (T) nucleus ( one p and two n). Would the D nucleus have to start with the much KE. Find the field strength in device that would give the D nucleus the required KE if the field is applied over a distance of .25 m.

http://h1.ripway.com/DrCherdack/Hon%20Unit%2042D%20Mot%20Sched08-9.doc

http://h1.ripway.com/DrCherdack/Unit10Worksheet2.doc

http://h1.ripway.com/DrCherdack/Unit10Worksheet3.doc

http://h1.ripway.com/DrCherdack/Unit11Worksheet1.doc

http://h1.ripway.com/DrCherdack/Relative%20Motion%20WS%20RM10-08.dochttp://h1.ripway.com/DrCherdack/Unit_2_worksheet_1.doc

http://h1.ripway.com/DrCherdack/Unit_2_Worksheet_2_.doc

Honors Unit 3 Test Results

The results of the honors quiz were not bad for 6th period and were not quite as good the results for the 9th period class. However, considering the quality of the students in the class, the results on the whole indicate that you had not had enough time to digest the several new concepts involved. Also some more practice in dealing with the concepts and terminology of electric fields and potential is clearly needed.

Therefore this test will be used as an assessment of where we were on Thursday not a judgment of your ultimate mastery of the subject. In other words don't sweat about its effect on your grade, relax and learn.

Honors Next Unit

Check here by Sunday Morning for the next unit. I am still pondering whether to move to two dimensional motion; collisions; or magnetic forces. Stay tuned for the exciting outcome.

We will revisit electric force and potential soon, so let it simmer on the back burner of your brain for a while.

AP Unit 3 Test

All those who received a score below 86 will be eligible for a makeup test next Thursday - not in class time. Sign up for it in the black book by Tuesday. It will replace your grade with up to an 86. I will use it and not the higher of the two so make sure you are prepared.

AP Unit 3 Test

Please turn in your Unit 3 tests Monday. I want to lower all your scores so you don't get swell heads. Actually I want to check and make sure I didn't take off points by looking at the wrong one of my answer sheets while rushing to get your results back to you.

HOnors Section 2 ( 6th Period)

Folks I owe about half of you a pretty big apology. I did use an electron as QTest in problem 2 in one version. In my hurry to get the tests back to you, I may have made some other error so Please return ALL Unit 3 tests on Monday.

Honors Assignment

Your assignment for tonight, due tomorrow, Friday 10/24 is:

1) Finish the lab which should have been done by yesterday or today but I'll let that go for now. Its just fill out the form plus a purpose and conclusion ( not a movie review on how much you enjoyed it)

2) Think about today's quiz and come in with two problems you would like to know how to do.

APSchedule for Unit 4 Work and Energy

Here it is:

http://h1.ripway.com/DrCherdack/AP%20unit%204%20Energysched-08-9.doc

http://h1.ripway.com/DrCherdack/unit4ProblemSheet.doc

http://h1.ripway.com/DrCherdack/Unit4worksheet1.doc

http://h1.ripway.com/DrCherdack/Unit4worksheet2.doc

http://h1.ripway.com/DrCherdack/NotesWorkandEnergyR3.doc

AP Ramp Quiz

Today's ramp quiz will not be an important factor in your grade, but it should alert you to the need to understand the physics and be able to present the physics in equation form rather than just crank through numbers using remembered patterns to get answers to numerical problems.

Honors Retest

Those who received a score (NOT A GRADE) of less than 76 on the last test can have a retest on Wednesday. It must be out of class hours; you must have all your Unit 2 Homework done by end of school  Tuesday; and you must sign up for it by class time Tuesday.

AP Components Lab

I was surprised to see that there is still some confusion over purpose of labs. Remember that they are parts of the scientific method. Their purpose is to confirm hypotheses. In this case the  first hypothesis was that the parallel component of the force of gravity on the cart was 

Mcart g  cos of the angle between the ramp and direction of gravity. This cos was simply h/L. 

The second hypothesis was that the perpendicular component of the force of gravity was equal to

Mcart g cos of angle between the perpendicular to the ramp and the direction of gravity. Note that this angle is the complement of the first angle and its cos  

= sqrt( 1 -(h/Lsquared)..

the third hypothesis is that acceleration parallel to the ramp = Fparallel/Mcart

The purpose was to confirm these by

1) predicted Fparallel using the equation from above and then measure the force it would take from the hanging weight to balance or cancel the component of gravity pulling the cart down the ramp. In other words did Mcart g h/L = Mhanging g ?  

Obviously, one needed to record the  h, the L, the predicted Fg parallel, and M hanging to accomplish this purpose.

Similarly, predictions and measurements should have been made and recorded for Fg perp and for a parallel.

All this should have been done for each of the three elevations ( angles). All quantities and all calculations should be included in your lab reports as well as purpose and conclusions.  In view of the fact that this somehow may not have been apparent to you despite our review of the a=F/M Lab, I will give 5 points of extra for every correct lab that comes in tomorrow and will not include any penalty on labs coming Tuesday.

All Students etc

I just got this from Ms. Bowden Please read and consider.

Hoboken Cares, a volunteer project based organization, is currently collecting "gently used" sneakers for children and adults in Jamaica. Many of the children & adults are mentally and/or physically handicapped and some are innocent young children born with HIV/AIDS.

I will have a bag/box in room 412 for all donations. The due date is November 5th. Please spread the word!

Keep in mind--- your sneakers will be the FIRST pair they EVER own!

AP Lab

Here is the lab sheet for the lab we will do on components of force. Note the actual lab performance will differ a bit from the write up

http://h1.ripway.com/DrCherdack/normal%20perp%20labwphotgatesR2.doc

Honors Test

If you have the last test in your possesion including answer or question sheet or both, turn them in immediately

AP Quiz

There was an error in the way I wrote question 4 on your last quiz. Two answers can be correct. If you had question 4 marked wrong return your test for gegrading

All Students Browsers

If you have trouble reading or downloading using the Microsoft Bowser, try downloading Firefox and using that as as your default browser. Also consider using Safari as an alternative.

Grades

Your grades were just updated for material handed in by 10/13. Thus there is some new stuff that is not entered yet.

Also, only look at the three categories not the total grade. There are very many labs outstanding in need of repair. I did not include these in your lab average, but if they are not fixed by Monday they will get low or zero grades, so clear up your errors for once and for all.

Honors Schedule

Managed to get this done so here it is.

NOTE worksheet Assignment for the weekend is Worksheet 1 Not 3

http://h1.ripway.com/DrCherdack/HonorsUnit3ElecStat-08-9.doc


http://h1.ripway.com/DrCherdack/Unit10Worksheet1.doc

http://h1.ripway.com/DrCherdack/NotesElectrostatic3-08r1.doc

AP Unit 3

I believe this is the missing link. NO not the one between ape and man. The one for units extra problems.

http://h1.ripway.com/DrCherdack/unit_3_extraproblemsR2.doc

These are the one you were to do in class last Wednesday but we had the quiz instead. Do 1-6 by Thursday

Techxplore team

Techxplore team members please attend a brief organizational meeting at 2:30  Wednesday afternoon in 506

Lab Data

Bring lab data for any lab you want to do or redo for labs. We'll be learning how to use a spreadsheet to help make calculations and graphs.

Honors Math Review

Her are some quick problems due Monday. You won't get extra credit for getting 9 right but you may make some big bucks in Vegas if you do.

Math Review Honors 10-11-08

In the southern hemispheric country of Upsidownia, penguins are strictly regulated. Each bunch must contain 12 penguins. A flock contains 144 penguins, but a gaggle contains 36 penguins. Penguins can circulate to or from any flock or any gaggle or any bunch.


1. Two flocks and three gaggles converge on an ice floe. They can reconfigure themselves into how many bunches?

2. Six bunches and two flocks land on a beach. They can combine into how many gaggles?

3. Eight bunches and two flocks are swimming in a bay. Seals eat two gaggles of them. How many bunches are left?

4. A bunch eats 12 kg of herring a day. How many kg of herring do two gaggles eat in a week?

The force between two charged particles, with charges Q1 and Q2 on them, is given by (this is real by the way)

F= 9,000,000,000 Q1 x Q2/ r squared; where r is the distance between them.

Charge Qa is 4 m from Qb. The force between charge Qa and Qb is 12 N.

5. If the distance is increased to 8 m what is now the force.

6. If the distance increased to 12 m, what is the force?

7. If the distance is decreased to 2 m what is the force?

8. If the distance returns to 4m  and Qa is doubled and Qb is tripled what is the force?

9. If Qa is doubled from its original value and Qb is halved and the distance is tripled, when will the Mets win the World Series again?

Techxplore competition

We will  (try to) compete in the Techxplore competition which is described  at the following site:

http://www.nstep-online.org/techxplore/default.asp  (not  a live link)

All we need is a few good men ( girls are you going to take this sexist remark lying down? _ Make sure I hear from you too) to bring glory to ourselves and the school - or at least have some fun and learn some stuff trying.

Contact me ASAP if you are interested.

Honors Physics Math Concepts Assignment

Write a concise definition or description of what each of the following mean:

Adding A to B

Subtracting A from B

Multiplying A x B

Dividing A by B

The ratio of A to B

Raising B to the power of A

How do you find the change or difference between two numbers?

How do you find the average of two numbers?


Be prepared to discuss all these in class Friday

a =F/Mass Labs

I am sure many of you are confused about the graphing for this lab so here is some clarification

1) Your horizontal axis really is  1/mass.  The scale should run from zero to about 1.7. The units should be (1/kg). The trial with the greatest mass, probably about 2.1 kg, is your first point. It should be plotted at about .47 for the horizontal coordinate. With luck it will be about .46 m/s2 for  the vertical coordinate.  The last point should be your lightest run. Its horizontal coord should be about 1.67 (1/kg) and the vertical coord should be about 1.6 m/s2. Note that you may have your acceleration in cm/s2. Too convert this  to m/s2  simply divide by 100.

2) Only for those who have spark tape data. 

For the tape data just do  a plot of the tape data  as a position vs time graph. 

I am afraid that the tape may have spoiled you first run. If it did, treat the first run as bad data and don't try to fit that point in your best fit line graph of a vs 1/m.

All Students Room Changes for Wednesday 10/8

To accommodate an inservice seminar in room 506 on Wednesday the following room assignments have been made:

Period 1 408

Period 2 408

Period 3 412

Period 3 412

Period 7 408

Period 8 412

Period 9 414

Students should report to PE for lab periods. My students will receive their quizzes in these rooms.

AP Extra Credit Solution

Here are two solutions to finding the theta required for a given delta x and delta y  and initial speed.   Mine starts with the ratio of x and y, and Charles begins with  an equation for x.

The second part of my solution owes itself to Charles' reminding me that 1/(cos squared)

 = tan squared plus 1. Thanks to this we both end up with an explicit equation for tan theta from which you can find theta.

http://h1.ripway.com/DrCherdack/Theta%20by%20Charles.doc

http://h1.ripway.com/DrCherdack/Theta%20GeneralSoln.doc

All Students

I have heard that many of you have three tests tomorrow. Therefore we will have our quizzes on Wednesday, even though I will not be in the classroom on those days.

AP Ferryman Lab

This lab is informal ( see your course guide) and since we sort of completed it Friday it is due Tuesday.

Make sure you did read the a=F/M lab.

All students: More good news

On Wednesday 10/8 I will be attending a a day long session on introducing engineering into a physics course. Therefore, you will once again be doing worksheets instead of having to deal with me. AP worksheets are contained in an earlier post. Honors will be posted on this blog Monday.

AP Extra Credit Opportunities

Put on separate paper from homework and mark clearly: extra credit. Due by Monday

For projectile motion

1. Prove that 45 deg is the angle giving the longest range if delta y is zero. A real proof not just 45 is in the middle. (10 pts)

2. Prove that range is the same for 30 and 60 deg if delta y y is zero ( 5 pts)

3. Find the equation for angle given delta x delta y and vi. Note the equation should yield two solutions some of the time and not solutions if delta y or delta x are too great for a given vi. Find means derive, not look it up!

AP Text Solutions

Here are solutions to some homework problems from your book

http://h1.ripway.com/DrCherdack/Solutions%20to%20Chapter%203%20Se.doc

Also problem 24 is just adding vectors: the wind has both east and north components which must be added to teh plane's 300 m/s . My recollection is final values are 387m/s east 50 m/s north.

Use Pythagoras and inverse tan to find magnitude and direction

AP Urgent.

Due to repeated failures of oncourse I am now posting links directly in my blog. Email me if you have any problems

Here are schedule, Ferryman lab to be done by Monday, labs for next week, Honors worksheet and extra problems for in class Wednesday, and sheets for homework and some extra sheets if you want to practice.

http://h1.ripway.com/DrCherdack/APunit3sched%2008-9.doc

http://h1.ripway.com/DrCherdack/ferryman%2010-08.doc

http://h1.ripway.com/DrCherdack/WorksheetF-2Hnr.doc

http://h1.ripway.com/DrCherdack/Unit3problemsheet.doc

http://h1.ripway.com/DrCherdack/Unit_3_Worksheet_1.doc

http://h1.ripway.com/DrCherdack/Unit_3_Worksheet_2r1.doc

http://h1.ripway.com/DrCherdack/Unit_3_Worksheet_3.doc

http://h1.ripway.com/DrCherdack/Lab%20on%20a%20=F%20divided%20bym%20AP.doc

AP Labs for Section 3

I need to see the Projectile Motion( Shooting for an A) Lab Reports from Christine, Jack, Patrick, Howard, and Ben. Please bring them in Monday.

AP Students

The Unit 3 Schedule Worksheets and labs will be posted by about 4:30 today so check AP materials and homework/events at my oncourse website.

All Students

Please check the out folders regularly. It's not very rewarding to spend time grading labs and see them sit in the folders for days on end.

Research Topics

Cool video http://www.asterpix.com/console/?as=1187646801883-e57383c789

Honors Sect 3 (9th pd)

After revieiwng your labs I have concluded that we are not yet where we need to be. Bring in yourtapes and data and all else from the constant velocity and free fall labs. Its what we'll do tomorrow.

Lab Resubmissions and See Me s

If you  a "resubmit" on a lab., make the corrections in a neat and orderly way. Often the best way is to edit your word processor document and turn in the new copy. Sometimes you can hand write in corrections or additions. This is true for some graphs and equations. This must be done neatly. In all cases write resubmittal on the top and fold in the original report if you are submitting a new one. This should be done within 3 days of getting the original back.

The same applies to labs  " see me" grades, although you must of course see me before resubmitting, unless I announce that I will address the issues with the whole class.

Grades in HAC

Pay no attention to the overall grade in HAC. I will calculate your grade differently to take into account certain strengths and weaknesses in your work and aptitudes.

In addition your extra credit including those from tests is a separate category that gets included separately in each quarter grade.

Use the HAC to see if you are behind in labs or homework and if there are any discrepancies between my records for these items and tests and what you think is correct. Do not use it for detailed grade calculations

Seating Plans

Tomorrow we will have new seating plans. I received zero input from anyone so far so these are my best guess. These will form the basis for lab groups and study groups, so think about any changes you would like to see. I will accept requests for next quarter. Make them privately

AP Labs

Several of you have labs or resubmittals that are overdue. Essentially, only the projectile labs should be outstanding at this time. Any outstanding resubmittals including labs marked see me should be in the in folder by Tuesday afternoon.  If not they will be given low grades. Any original not in my hands by Thursday  will get a zero. 

AP Projectile Lab

Note that you lab does not have address what is called conclusion in the lab sheet. Focus on the analysis and results. Do explain your reasoning behind your calculations and how you found vifor the horizontal shot and eventually  delta x for the diagonal shot.

What I mean by reasoning is something like time of flight is change in velocity in y direction divided by a in y direction and vyf can be found from kinematic equation Dy = (vyf squared- vyi squared)/2a rewritten for vyf.

Your conclusion should refer to how successful you were in learning and applying equations governing projectile motion.

Honors Section 2 ( Period 6) Labs

Four of the Section 2 students have not turned one or two labs or not resubmitted a lab.  These are late as of close of school Friday and will receive lower grades. Labs not received by Tuesday close of school become zeros and will have a real effect on you first quarter grade. If you think you turned in a lab that you do not get back tomorrow, see me immediately after the class begins tomorrow's lab. 

Honors Worksheets

I have posted 4 new worksheets under Honors Materials. These are to be done on Tuesday and Wednesday in the following order: Force WS 1 Force WS 2. Physics WS F1-1R1, UnifAccWS1. Complete at home what you don't finish in class.

All Students, Good News

I will be out Tuesday 9/30 and Wednesday 10/1. Bring in worksheets as noted in your schedules so you don't waste time not doing physics (and driving the sub crazy). They will be collected on Wednesday, so that I, like Santa Claus, can see who has been naughty or nice.

Urgent Honors Lab

Folks, your lab for this week is posted under Honors Materials. READ IT TODAY. Remember, reading quizzes are possible!

Worksheets will be posted within a couple of hours; as soon as I think of ones tough enough for such  talented students.

AP Homework

Much of the homework shows very original and some very quaint approaches to many of the problems. IF only these new approaches were anywhere near correct. We will spend the next day or two reviewing the basics of kinematic equations once more. Bring in all your homeworks for kinematics and your Physics Tours Mini Lab.

I will continue to insist that you write equations explicit for the quantity being found. I will also continue to demand that you understand where your equations come from rather than just quote the text or other source.

Honors Research Auto Transmission and Torque Convertor Site

Hey gang, try this site. Use the next and back to move from page to page and the up  for the table of contents. There are sections on automatic transmissions.

www.tpub.com/conent/construction/14273/css/14273_165.htm

AP Shooting for A Lab

Do not do the conclusions, just show all calculations and your prediction and the actual distance ( when we get that far)

Honors Free Fall Lab

1)I have posted a copy of the free fall lab sheet under Honors material.

2) N0te that Column E is found from Column D/delta t. (it originally said Column C/delta t).

AP Review Sessions and Study Groups

1) There are about a dozen students in my AP classes who are struggling at the moment. This is largely due to lack of facility with some key math elements including algebra and trig. This is largely very curable. I will hold review sessions twice a week to help remedy this. Please get together with each other and decide when it would be best to hold these sessions. They can be before school MTWF and after school MTThF. 7th period MTWThF or 2nd MTW could also work.

2) We will soon establish study groups including every student. These will be required to meet at least once per unit, for 40 minutes minimum outside of class hours. Let me know about specific preferences or needs before I assign groups.

All students: Not all curves are exponential

Many of you have picked up the bad habit of referring to all non linear curves as exponential. Exponential growth means the quantity goes as a constant to the t power i.e. K raised to the t power.

K to the t is very different from t to the k. In our constant acceleration labs displacement went as t squared or t to the 2, not as anything to the t power.

Curves that goes as t squared are parabolic not exponential.

Honors research Topics in Physics

Your vacation is almost over. Its time to pick your topic folks. We will finish up the mysteries and intrigues of transmissions and move on to the differential. We amy get back to combustion for a day or two, but you proposals for your independent work are due Friday. It should be a couple of paragraphs about what you will cover and how you will present your results. The word powerpoint is not a sufficient description. I'll try to approve them all by Monday. Real outlines with references are due the following Monday.

Honors Schedule for Unit 2

he schedule for Unit 2 will be posted in 5 minutes, I hope. Worksheets etc. to follow i na few days.

AP Vector Lab

I must be getting soft. DON'T do the extension.

Do read the post of Saturday

Grades Posted

I have posted your grades and they should appear on the HAC.

1) I cannot see  what you see  on HAC so I am not sure if its saying what I told it .

2) ME means you will take a makeup exam

3) Honors has had only quizzes so far and so the test grade, which is a weighted cumulative for all three quizzes, is still not really a major factor in your grade AND more conventional material and tests will be coming. Also labs have not been included yet and those of you ( usually  a great majority) who are willing to put some effort in will do well on labs. Therefore do not be discouraged if your current grade is low, and don't become overconfident if your current grade is high.

AP Labs

1) The free fall lab is due Monday. It is a formal lab. See your course guide for how to prepare your report. You may use a spread sheet and its graphing features.

2) The vector lab is due Tuesday. You must show the two vector addition drawings specified in the lab and provide a one or two sentence summary of the lab. Also, you must answer all the questions in full sentences or equations such as A+B= etc.. You can do this on the lab sheet itself if you can do it neatly enough for me to read it. Nothing else is required for this lab.

Engine Physics

Here is the site Sarah found:

http://www.mb-soft.com/public2/engine.html

For tonight, figure out how many joules of fuel energy we need for one cycle of one cylinder based on the watts ( joules /sec) required to produce 241 Nm (or joules per radian) at 3000 rpm.

The cylinder is one of six and only fires once every two revolutions. Assume 100% efficiency and we'll correct for that tomorrow.

Honors Assignment

Your math worksheet assignment is posted on the website. Look under Honors Materials for some notes and a worksheet.

Forum on Medicine Summer Program

There is a national Forum on Medicine summer program for students interested in medical careers. It is costly but students who have taken have liked it. See me ASAP for info

AP Unit 2 Schedule etc

The schedule and materials for Unit 2 2 Dimensional Motion are posted under homework and under materials.

Honors Material

See the website Honors Material for some notes on converting heat to usable energy ( or eat to energy)

Honors 9th period ( Section3)

At the conclusion of class today there were two spark timers and one buggy left out. If they are still left out by the beginning of second period you lab grades will be severely reduced.

AP Kinematics

I am posting some notes on today's lesson in AP Materials. The title will be something like Kinematic Equations vs Quadratic Formula. I'll also posted solutions to problems 51 and 58 and the balloon parachute jumpers problem.

Correction to Honors Lab

The second sentence on the lab should say 10 Hz NOT 1/60 th.

AP and Honors Kinematics

This post contains information that is a review for AP and needed by Honors to do the lab.

Kinematics is the study of motion, kinematic quantities include position (x), displacement delta x = (xf -xi), velocity v = delta x /delta t or ([xf-xi]/[tf-ti], and acceleration a delta v/delta t or ([vf-vi]/[tf-ti]).

x at the end of the interval = xf, x at the start of the interval = xi; i.e. f is for final value and i is for initial value



To find the velocity for a given interval of time simply find the change in position and for that interval of time and divide it by the time that interval lasted.

To find the acceleration for a given interval of time simply find the change in velocity and for that interval of time and divide it by the time that interval lasted.
velocities or accelerations can be average, if the interval includes the whole period of motion, or instantaneous, if the interval is a relatively short time within the period of motion.
Position is typically plotted on the vertical axis and time on the horizontal axis.

Slope mean change in vertical coordinate/ change in horizontal so for a position vs time grpah slope = delta x/ delta t.

Lab Sheets for Honors and AP

Check the materials pages of my website. I am posting lab sheets there. Note that somehow Oncourse decided to leave out the first letter of the titles such as the H in Hon and the A in AP, but just download them, print them, and bring them in for you lab this week.

Honors Section 2, please use the revised sheet you will find there, except realize that most of you chose time intervals of .3 or .2 seconds rather than .1 sec, so adjust accordingly.

Project Opportunity

An organization promoting science and engineering education is running a competition. Teams are asked to develop an invemtion that solves a real life problem. For example, some way to get light where you want it without wasting light on the rest of the room, assuming where yu want it changes and you don't want to wear a head lamp. Or something like a thermostat that detects whether there is someone in the room and adjusts itself accordingly.

The competition is strong but the rewards are impressive: recognition, visits, lectures from Nobel Laureates, showing your folks you're not as dumb as they thought you were.

Email me if you are interested and I'll get you the details.

Topics in Physics( Honors Research 1st ,8th periods)

Your current assignment is to find read and try to digest material on basic flame propagation or explosion propagation that is relevant to what goes on in an automobile engine.

You should have your material selected and at least perused ( looked at) by tomorrow.

Our discussions tomorrow and probably Thursday however will focus on, force torque, power and rotational motion. This does NOT mean you are off the hook for the assignment until Friday.

Problem Sheets, Worksheets, etc.

Home work is to be done on clean sheets of paper not as markups of problem sheets or other handouts. Marked up sheets will not receive credit as homeworks.Homework should show evidence of work performed not just answers.

Honors Quiz

After all that gloom and whining I expected the worst when I graded your quizzes. Fortunately that's not what I saw. The median grade was a B+ in H2 and a solid B in H3. 

Not bad guys; I guess you did learn somethings in the past two days.

Average velocity

To find average velocity when an object travels at each velocity for a different period of time you cannot sum the velocities and then divide by the number of velocities.
vavg = (v1+v2+v3)/3 is not right unless delta t1 =delta t2 =delta t 3.

In other words this method only works when the time periods are the same for each velocity.

AP Math Review

The Unit 1 Math Review is now posted in AP materials and homework. It is due Thursday

AP Math Review

Sorry guys about the math review. I'm not really crazy about it and I meant to revise it before posting it. I just forgot it was due tomorrow. I'll revise it and post it on the website to be due Thursday.

Text Books

Text books are not needed for class unless you are specifically told to bring them in

AP and Honors Assignments

1) Everyone, Student info forms and the signature page from your course guide are due tomorrow Tue 9/9

2) Everyone, send me an email with you name in the title, extra credit if you get your parents to do the same

3) AP-3 ( 3rd period class) Your first two text book assignments are due Wednesday. AP-4 your first text book assignment is due tomorrow Tue 9/9

Physics Club

Physics club officers and members. We should start thinking about the fall.  Can we have one after school meeting per month to accommodate those who can't make mornings?  What topics would you like to present? Is there a less expensive way to supply the bagels?

E mail your ideas to me.

Honors Research Topics in Physics

Those of you taking this course can email me with any preferences you have for topics you would like to cover.  Samples from a previous year include:

1) Fusion power including: plasma physics, magnetic confinement, fusion reactions, thermodynamics of power generation, and electromagnetics and details of electric generators

2) Particle physics including: special relativity, collisions between electrons and nuclei, designof accelerators, particle detectors

3) Electromagnetic waves including: optics of the eye, TV signals, operation of cathode ray tubes 

Honors Research, Topics in Physics

All those taking or hoping to take honors research Topics in Physics stay tuned. There will be info on the subjects and a first period section may open up.

Summer and Projects

I have taken home a large Knx project and awarded a leaf blower to the physics department. If you would like to undo either of these allocations, let me know via email immediately.

To all of you, thanks for your work, patience, good humor and interesting personalities.

All those taking or hoping to take honors research Topics in Physics stay tuned. There will be info on the subjects and a first period section may open up.

Urgent Honors Period 2 Anonymous Hwrk

I have a large mass of thermo and Fluid Homework with no name from period 2 . E mail me immediately if you are the culprit

URGENT ALL STUDENTS PIck up Projects

All projects in my room at noon Thursday become my property to keep or dispose of as I see fit.

Come get your stuff if you want it!!!

Great Adventure

Reading your labs is the great adventure. It seems that many of you entered an entirely new universe at the amusement park. If you are still working on ours, try to avoid creating a whole new regime of physics. Try doing some intelligent observation and deduction. Your mass in Kg is your pounds/2.205 something between 50 and 90 kg for most of you.  Momentum changes if speed changes and momentum is low when you go slow no matter how high you are. PE increases with height.

For example:

Most of you seem to think that when you feel a force 3 times your weight you actually feel lighter than normal. 

Some of you think your mass is about  6 kg, the equivalent of 13 lbs. Many of you think we should use pounds instead of Newtons for wieght in metric calculations. You seem to forget that your weight is mass (kg) x g    (g  is 9.8 N/kg on earth).

Some of you claim the outer and inner ring of horses on the carousel were just .3 m apart, i.e. 1 foot. It must have been pretty crowded on that ride.

Some of you think the inner horses go around more rotations than the outer ones. Neat trick

Others think the horses go up and down 65 or even 90 times per rotation  of the carousel. That would be a pretty exciting ride. A few said the ride took 3 minutes to go around once, because the period is the time to amke one cycle, not the time from the start of the ride to when it finishes

Many of you confuse momentum and energy. In fact you use the word momentum with no indication that you know what it means. To say the ride builds momentum as it rises even though it nearly stops at the top of the first hill, is to show you really don't know that momentum = mass x velocity. To say momentum is the the same throughout the ride is worse since the v is very high at the bottom.

Most of you can recognize that KE = m v^2/2 especially when it is written o every second page of the lab sheeet.  Some of you say that maxium KE and maximum speed occur at different places, even though KE is proportional to speed squared. Can maximum speed squared occur at some place where the speed is not the maximum?

Some of you think gravity was pulling you upward at the top of the loop, this is a most unusual direction for the gravitational force.

There is more, but I must go back to reading the installments in science fiction and fantasy you have prepared for my entertainment.

Honors 1 Lens Labs

The following are in jeopardy of  no credit for their lab on convex lenses:Kyle, Meaghan, Chris, Brett

 because your ray diagrams having nothing in common with correct ones. To receive credit you will have to provide correct drawings of the four cases [ do is object distance] do >2 f; do=2f; 2f>do>f; do

This is not so tough because these ray diagrams are in the notes on geometric optics you were to have downloaded and read 3 weeks ago and that you'd better be reviewing for the final.

Andrew, Mike, Dennis, Steve and Anne Marie should also do this if they want decent grades for this lab.

Sorry for being so public, but I haven't been able to connect with the Bernards mail server today

Additional Honors Review Material

Don't panic, its not much

RevShtHnrsSpring-08Add.doc

More solutions to Honors Review are to come

Let me know by email if you can't read these ALSO. There will be a little more review material on magnetics and thermo and maybe circuits so stay tuned.

Honors Review Spring –08 Solutions Prt2

IX. .1 .482 V Toward B Away from A IX.2 1.73x10¹⁰ Vthis is one reason why whole uneutralized coulombs are not found in nature. IX.3 1.92x10^-16 J. IX.4 28.3 ohms; .21 A; yes;I_B =.14 A I_C = .07 A; V_A = 3.2 V V_B=V_C=2.8 V; P_A =.68W P_B = .392 W

P_C = .196W

X. 1 B= 1.4x10^-5 T. X.2 F=1.1x10^-11 N X.3 EMFor voltage = 3532 V

Optics page 27

1. try it but don’t waste any time 2. di = 30cm Mag = 2x 3. AM radio low end of frequency spectrum gamma rays high end 4. 4.37x1014 5. 1.18x10^-14 6.Light passes through real image, light only seems to come from virtual image 7. q_incident = q _refl

8. di =27.5 cm Mi = .83 9.missing in action 10.di =26.7 cm M =1.667 11. f = 30 cm 12 do =15 cm

Refraction and more lenses Page 29

1. ni index of refraction for 1st ( incident) material nr index for 2nd (refracting ) material

qi angle incidence, qr angle of refraction. refraction: bending of light at surface between two materials as speed changes total internal reflection light bends so much away from normal it doesn’t penetrate second material i.e. qr = 90 deg happens only when nr

3. c = 1.94 x10⁸. 4.sinq water /sinq lucite = n_lucite/n_water q_water = 37 deg 5. sin 90 =1 so sinqcrit = n_air/n_water.=1/1.33 qcrit = 48 deg 5. n_gem/n_air = 1/sin 41 = 1.52 so n_obj =1.52 its glass 6. nmatl = sin 37.5/sin 25.6=1.4 7.b 8. total internal reflection and diffraction of sunlight inside water droplets ( don’t waste time on this now) 9. reflection light bounces off and is not transmitted into new medium, refraction: light bends as it enters new medium 11.C its virtual and erect 12. D bends away from normal 13. q_reflect = 45 deg, q_refraction = 32 deg 13. do = 2f so image is real inverted same size di = 2f = 20 cm

15. cglass = 2x10⁸m/s 16. c 17. A 18 still 48 deg.

AP FINAL

I just spoke with Mr. Howlett and because of the contradictions in information provided to teachers and students by different parts of the administration we have decided on the following policy. The final is now optional for all students who took the AP exam, which is all of my students.

The exam will allow you to raise your grade. It will be graded on the very liberal AP scale 39% is a C 50 % is a B 65% is an A. It will comprise 70 MC and two FR from a real AP. To prevent your taking it without studying it will count whether it raises or lowers your grade.

You must respond to ASAP so I know if I have any takers for Monday morning.

Dr. Cherdack

Honors Review Solutions Part 1

Here are solutions for the first half. Stay tuned for more solutions and more news about what you need to know

HnrSprngRev08solnspt1.PDF

SHM means Simple Harmonic Motion

SHM means Simple Harmonic Motion. That's it that's the purpose of this post

Mathematical Homework and Review Solutions

Homework: you must do 3 problems from each of the 11 groups of problems, you must show work, not copy answers or my calculations and you must choose real problems or essays, no one or two word answers. Its due Friday at the exam.

Also, BRING IN YOUR BOOK

Here are the solutions . Let me know if I have to post a link or you can read this well enough.

Mathematical Physics Final Exam Review

Solutions to Problems

Oscillations and Waves

1. 1/5 or .2 Hz 2a. .04 s 2b. T = 2pi sqrt(m/k) ; m= 2x10^-4kg 3. T =5.44 s

4. 2250 N 5. 5. 900 N 6. 3.11 m 7. 136 Hz 8. 670 nm 9.a because the wavespeed increased 10. no drawings here come see me if you need to 11. c = srqt ( F_T/(M/L)) = 44.7 m/s first harmoci l = 2l = 4m F 44.7/4 = 11.2 Hz 12. c 13. b 14. a 15. b 16. b

17. 1 s ; 1Hz; new period =1.41 s 18. Waves in phase amplitudes add, produces maxima in light or sound or whatever type of wave 19. b 20a 21 k is spring constant in N/m; x is distance from equilibrium point 22.more

More Waves page 8

1. 1.3m 2. 30C 3. 103,000 Hz 4.no for both 5. c =256 x( 4x.33) = 338 m/s 6. 2L = c/f , L= 340/786 = .43 m 7. 6.3 Hz 8a. f = 850 (340/340-35) = 944 Hz 8b. f = 771 Hz

9. waves reflected from bottom arrive at top in phase with waves created or reflected at the top. 10. Open tube 2L =l or f =c/2L =343 Hz

More waves page 9

10. L = Nl/2 so f= c/l = Nc/2L

putting a cap on it changes it to one end closed L=Nodd l/4 or f=Nodd x c/4L

11.B 12. A 13. D 14.B 15. hot

Optics page 15

1. try it but don’t waste any time 2. di = 30cm Mag = 2x 3. AM radio low end of frequency spectrum gamma rays high end 4. 4.37x1014 5. 1.18x10^-14 6.Light passes through real image, light only seems to come from virtual image 7. q_incident = q _refl

8. di =27.5 cm Mi = .83 9.missing in action 10.di =26.7 cm M =1.667 11. f = 30 cm 12 do =15 cm

Refraction and more lenses Page 17

1. ni index of refraction for 1st ( incident) material nr index for 2nd (refracting ) material

qi angle incidence, qr angle of refraction. refraction: bending of light at surface between two materials as speed changes total internal reflection light bends so much away from normal it doesn’t penetrate second material i.e. qr = 90 deg happens only when nr

3. c = 1.94 x10⁸. 4.sinq water /sinq lucite = n_lucite/n_water q_water = 37 deg 5. sin 90 =1 so sinqcrit = n_air/n_water.=1/1.33 qcrit = 48 deg 5. n_gem/n_air = 1/sin 41 = 1.52 so n_obj =1.52 its glass 6. nmatl = sin 37.5/sin 25.6=1.4 7.b 8. total internal reflection and diffraction of sunlight inside water droplets ( don’t waste time on this now) 9. reflection light bounces off and is not transmitted into new medium, refraction: light bends as it enters new medium 11.C its virtual and erect 12. D bends away from normal 13. q_reflect = 45 deg, q_refraction = 32 deg 13. do = 2f so image is real inverted same size di = 2f = 20 cm

15. cglass = 2x10⁸m/s 16. c 17. A 18 still 48 deg.

Electrostatics Page 23 etc.

1. gained extra electrons and now repelled by extra electrons on the dome. 2. Gives electrons somewhere to escape to and can provide electrons when needed. 3. 9.6 x10⁴ C

4. .225 N away from 5. r² = q_Tkq_S/F so r = .135 N 6. E= F/q =3x10⁶

7. q = .6/24 = .025 C 8. 9.6x10^-12 9. excess electrons flow to leaves and repel each other, finger drains excess electrons 10. conduction tough rod to scope; induction hold rod near scope and allow some electrons to leave scope and go to finger. 11 Lines go from positive to negative. Lines are twice as crowded around positive charge since it has twice the charge.12. Missing info

Capacitance and Potential Page 25 Note correction last equation for DV on upper page 25 is DV =E dot d

1. Capacitance, voltage drop, charge, potential energy, distance, 9x10⁹,electric field

2. Coulombs, joules, Farad, Newton, Volt, meter, N/c or V/m. [the other]2. .101 J

3. 7.2x10^-8J 4. 10^-6;10^-9;10^-12 5.q=CV = 1.125 nCoul. 6. Cq/V =5.8 mF.

PE =QV/2=1.05x10^-4 J 7.this one is on you do it 8. 5V 9. store charge and energy ( really they pass AC and stop DC but that’s to advanced for you,) metal plates close to each other with air, plastic, or vacuum in between.

Currents and Circuits Page 29

1. electrical potential ( voltage); current; resistance; power. 2. beginning with Watts ending with farads: 10,9,7,1,5,6,8,4,2,3. 3 17 ohms 4 5V ( again) 5.d 6 b 7. 14.7 ohms, VI = 3300Watts, 9.9kWh 8. your turn 9. P =V²/R so R = V²/P = 192 ohms 10. 5kW x 12 x 92 days = 5520 ( about $800 these days) 11 ran away 12. a 13. b 14. rubber 15. copper 16. c 17. b 18. 1 ampere 19. potential energy per coulomb, volts 22 resistance to electrons flowing when voltage is across element, ohms 20.same voltage at all points on bird, no field in bird so no current 21 no effect I = V/R =2V/2R 22.( right place this time) dimmer, share the voltage each gets fewer volts. 23. a. 12V of course, b. I=12/7 amps, c. 7 ohms d. 12/7 amp – same- everywhere in series circuit. 24. pull a bulb out if others light parallel if not series. 25. b) 30 ohms c) 4V d) 1/5 amp 26. b) 6.67 ohms c) 12 V across each parallel resistor, d) 12/20 amps = .6 amps

27. R equiv = 4.4 ohms I circuit = 48/4.4 = 10.9 A

	2 ohm	4 ohm	6 ohm
I (A)	10.9	6.55	4.37	10.9
DV	21.8	26.2	26.2	48
P ( W)	238	172	114	524

28.D 29. D 30. C 3Amps 31. C 60 V 32. D 360 W 33. 2 A Total resistance is no 30 ohms total current is 4A and half passes through meter. 34 all of a,b, and c are true 35. d

36.75 watts = .075 kW .075 x 168 hrs = 12.6 kWh at $.1 per kWh costs= $1.26

37. b 38 T 39. T 40. T 41. F 42. F 43. T

Magnetism Page 34

1. A 2. 2 x10^-5 T 3. No only component perpendicular to field yields a force

4. F = 1.6x10^-19 x 3x10⁶ x 2 =2.3 x10^-12 N 5. EMF = -200* -1.6*.02/.2 =32 V

Fluids page 35

1. 90,000 N 2. 131,000 Pa 3. FB = 2.5 m3 x 1000 x10N/kg = 25000N 4. Use Bernoullis’s P₁-P₂ = 0 v₁ =0 so v2 = -2 g(h₂-h₁) = -2x10x (-3) = 60 so v₂ = 7.75 m/s

Thermo dynamics page 35

1. isothermal 2. n = 60 moles 3. 2x106 Pa 4. PDV = 5 x10⁶ J , T intitial = PV/nR =241 K, T final = 1444 K