New Year

Have a Happy and Safe New Year. Looking forward to working with (nearly) all of you in 2010.

Have a Happy and Safe New Year. Looking forward to working with (nearly) all of you in 2010.

.... and keep thinking physics, its what's all around you.

Honors Assignment on Magnetic Fields and Forces

Read the notes posted here. Answer the sample questions up to but not including the ones on Magnetic Induction - except the generator groups, you get to do it all.

I'll try to write some notes on plasma particle and energy loss in the next day or two, so make sure you stay tuned.

http://h1.ripway.com/DrCherdack/Notes%20on%20magneticsR8.doc

Honors Fusion Power Plant

I will try to post notes and problems on plasma, heat transfer, thermodynamics, magnetics, and structures on a general level so you all can have an overall grasp of the physics behind the entire plant. As you may imagine, this may take some time so keep checking this space. At this point I believe, each group should have some understanding of their own specialty from reading notes and the relevant passages in your text. You should be meeting.

By the way, the I in magnets is current, i.e. amps or Coulombs per second; and NOT impulse (which of course is J for Jimpulse).

Archimedes Lab

Many of you folks still miss the point. We did not need to use a lab to find a number we can get out of a table, e.g. the density of the brass block. The purposes of our labs are almost always to confirm an hypothesis we formed from observation and translated into equations or one we derived from other related observations and proved hypothesis.

The main purpose of this lab was to demonstrate that FB = rho g Vol sub. If, by using a volume obtained using this equation, we got the right density, then the equation is correct. Errors of a few percent in the measured vs expected value of density offer pretty compelling confirmation of our equation, i.e. Archimedes principle

The second purpose was to try to verify that change in height of a fluid changes the pressure in a vessel according to delta P = rho g delta h. Many of you were much more succesful in this than I expected, getting errors of 10 % and lower. Good work.

AP Break Package

Here is a link for the first part of the package. Make sure you read the handwritten notes for the oscillation questions ('95 questions 1 c and d). Also skip the '94 question you are not ready for it. [it just kind of snuck in there].

http://h1.ripway.com/DrCherdack/APDecBrkPckg.PDF

Greetings

Hope this Christmas has been a a happy one for you. While this time has a particular meaning for those who celebrate Christmas, this break in our usual pattern of life is a good time for all of us to think about those people who, and those things that, make life worthwhile... and I don't mean Brad Pitt or new ipods.

Make the best of this time and I'll save my tirades about your lab reports for some other time.

AP Assignment

Complete the review package by tomorrow morning,. It will be counted as 6 homeworks.


All right; stop your whining; its due Monday right after break.

For those who were out, here's a link to part of it. I may get the rest up soon or even during the break so keep checking.

http://h1.ripway.com/DrCherdack/AddlMechRevQuest08-9.doc

Honors Assignment

Read the notes and do the problems in the notes and WS1 tonight.

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

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


http://h1.ripway.com/DrCherdack/Nuclear%20Reaction%20Rates%20WS%202.doc

AP Package

There is a two part Mechanics Review package in your out file. Make sure you get both pieces. You'll be doing it over break and its worth 6 homeworks

Honors Homework

Assume:
electric power needed is 750 MW,
efficiency of conversion of fusion power to electricity is 45 %
plasma volume is 200 cubic meters
energy per reaction is 2.9 E-12 J
assume nD = nT = 1/2 of N fuel [ number of fuel nuclei per cubic meter]
sigma v is 7 E-22 cubic meter per sec [yes these are the units for the reasulkts to come out correctly]

Find the following:
fusion power required
fusion power per cubic meter of plasma
reactions/ ( cubic meter sec) required
nD , nT

20 extra credit points if you get it right, show all work and DON"T just copy

Fluid Review Solutions

Hopes this helps

http://h1.ripway.com/DrCherdack/Soln%20Sh%20Fluid%20Dynamicsr1.doc

Honors

We will be spending the next three days on projects. You will also have a large assignment on your project over the break.

Your assignment for Monday is:

All re-read the relevant sections of the European power plant report. This means the summary and whatever annexes apply to your specialty.

Plasma and blanket groups have some real meat to digest right in the report. Plasma group, identify density (number of fuel nuclei per m cubed), volume of plasma and confinement time. Start to understand energy and particle loss mechanisms.

Heating group should go back to the ITER website and be clear on power, energy, currents, type of ions, etc. You should also be clear on microwave heating including the ion and electron cyclotron frequencies and powers produced for ITER.

Magnet group. Make sure you understand the directions and purposes of the OH, Toroidal , and Poloidal fields and the configuration of the coils that produce them.

Read these notes [don't panic we will go over them in class]:

http://h1.ripway.com/DrCherdack/Notes%20on%20magneticsR6.doc

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

Plasma group read the above notes also.

Thermo group. Read this

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

and then look in text to understand thermal conduction. Heat must be transferred from lithium to water/steam by passing through tubes containing the water/steam that are immersed in the lithium. Find the equation for this heat transport and figure out the following: assume the tube wall is 1 cm thick. Assume the temperature difference between the water/ steam and the lithium is about 200 C. How many square meters of surface area are required to transport 2.5 E9 Watts of thermal power. Look up Rankine cycle and steam turbines. Identify 4 web pages that will help you design your turbine cycle.

Generator group: read text on magnetic fields and magnetic induction. Know Faraday's Law and what it means. If the changing field goes from +B to-B in 1/120 th of a second, and the coils that the voltage is being induced in have 100 turns and a coil area of 2 m square, what is the required value of magnetic field strength B to produce 20,000 V in the coil. The coil will be wrapped around soft iron so mu is not mu 0, its about 1000 mu 0 ( mu is the greek letter that looks like a fancy u).

E mail

You guessed it: can't reach our school email again.

AP Fluids Problem Sheet

This is a newer version of the fluids problems which addresses some refinement of the wording of some problems, etc.

http://h1.ripway.com/DrCherdack/Unit%207%20AP%20Prob%20Sh-06R2.doc

Ballistic Pendulum Lab

Too many labs say delta PE = delta KE. This is not true. Everyone should be aware that IF Win adn Qin adn delta Eth all =0, then delta PE equals the OPPOSITE of delta KE, i.e PE gains what KE loses and vis versa.

In this particular lab all the KE right after the collision becomes PE when the motion stops. Thus for the period beginning when the collision ends, and ending when the pedulum reaches maximum height, delta KE = O- KE' = -KE' so delta PE = --KE' or KE' = delta PE, but only in situations like this and note again that KE' is the intial KE befoer the PE starts to increase.

All Juniors Physics SAT II

Many of you should considering taking the Physics SAT II test. Only about 50,000 take it and so even just doing okay on it may help you get into some place you probably don't belong........ I mean you will appropriately challenged. I will do after or before class coaching from about mid May to the first week of June. If you are in AP, taking the SAT II in May might work, but June would be better. June would definitely much better for honors.

Honors test

Because the PSAT scores will be given out in science classes tomorrow the Honors Test may be divided into two parts with the nuclear and 2 D problem given on Friday. We'll see how it goes.

Email

Surprise Surprise, our email's not working. I can see you've sent messages, but they won't open in Internet disaster or firefox, so I an' read what you're asking me. Sorry

Collision and fusion problems

Here are solved copies of recent classwork problems. If this link doesn't work its also posted on the homework page on my oncourse website

http://h1.ripway.com/DrCherdack/samplecoll%20probs.doc

Missing Medical Program form

Someone removed the form for the Youth forum on Medicine from my computer desk. Please return it ASAP.

Bring Cans by Noon

Last chance to show you care about others, do it!

Honors Assignment

Complete problem 1 on Collision Worksheet1 and problem 1 on Collision Worksheet 2 and do problem 9 on the "Extra Problem Sheet ..... and I have no idea why anyone is using a 1.2 kg bowling ball.

Collision Worksheet 2 Problem 1

Ignore, in fact cross out, the words in parentheses. Just find delta p in the x direction and in the y direction. The momentum transferred to the blade would be would be the same magnitudes but in the opposite directions ( x instead of - x and -y instead of y). Energy transferred to the turbine blade is just KE lost by the steam.

Honors 2D Momentum and Forces

Lets do some two dimensional collisions. Problem one on Collision WS1 and problem one on Collision WS 2. These were posted on 11/15. What you have to remember is that the momentum equations now work as 2D vector equations.
m1v1x + m2v2x = m1v'1x + m2v'2x and m1v1y + m2v2y = m1v'1y + m2v'2y and of course components, components, components.

Future Doctors

There is a program called the National Youth Leadership Forum on Medicine. While I believe it is costly, I have heard good things about it from students in the past. If you would like to consider it you must tell me by end of school Wednesday. If you do consider it, I would suggest you check it out carefully before you commit, but that is well after I nominate you, so tell me ASAP if you want to be nominated.

Calculators

I have one with a girl's name beginning with C carved into it. The office has about eight.

Honors 2 Labs

i need to discuss labs with Scott, Harold, JB, Dean, CJ, Maria, Ben, Jen, Monica, and, not to be left out, Tony. See me before or after class but no missing gym.

AP 2 Labs

Missing grades on labs from Brad, Cal, Wave, John, Katelyn, and Armon. See me before or after class- no being late to next class though.

Honors 1 Labs

Missing grades on labs from Miguel, Claire, Stephanie, and Carly. See me before or after class- no being late to next class though.

( I'm not missing any labs from Ashley and those brownies were too good.)

AP 1 Labs

Missing grades on labs from Jay, Audrey, David F and Scott. See me before or after class- not being late to next class though

AP Test Results

I am mulling over how to treat your test scores. The test was straightforward and not all that difficult or long, but I did not provide any equations, etc. and you do deserve some credit for getting most of that stuff right.

I'll let you know in a day or two and then post it on Home Accident.

Honors Test 2 items

1) There will be a sort of retest on Thursday, it will include a question or two on 2 d forces or momentum, but mostly a retest of the most recent disaster.

2) Your grade on the last test is the greater of your score x 1.25 or your score + 17

AP Power and Energy 2 items

1) Some folks are still missing the point: power is the rate of transfer or transformation of energy. It does not have to go into changing Ek. When a car is accelerating up hill, power from the engine is going into raising EP, EK, and combating friction and air resistance ( changing Eth and overcoming losses to outside the car - call these losses to outside a negative Qin) all at the same time. These are all the things that can comprise work and power is just the rate at which work is done.

Mav is only the rate of change in Ek. Mav usually = Fnet v, but power from a force involves the total of that force, not just what is left over after subtracting the forces opposed to it. If you don't believe me run up 100 flights of stairs at a constant speed (Mav =0) and let me know how little power it and work it took. The power supplied by a particular force may usually be found from multiplying that force by the velocity in the direction of that force, but this not fool proof. Consider two train engines or bulldozers (or Sumo wrestlers for that matter) of different powers pushing in opposing directions. The engine that is overpowered is exerting a force opposite the velocity but it is not putting out negative power. Its power is going into friction or tearing up the earth or ripping apart metal. The work kinetic energy theorem is incomplete at best and downright misleading often.

2) AP Section 2 tests - I am the nameless committer of the error. Thus the need for reclaiming your tests. Put them in the test folder Monday.

Honors

You should be able to do AP Worksheet 3 problem 2. Remember that velocity of plane as seen from ground is velocity of plane as seen the by air plus velocity of air to ground ( i.e. wind velocity). All addition is by components. Keep in mind that the velocity of the plane with respect to the ground has a zero component in the North direction. Use this to find the north component of the plane's airspeed and then use that to find the angle of the plane's air speed.

AP Section 2

Someone who shall remain nameless made an error in his answer set. Please return your tests on Monday.

AP Two Items

1) Please change the header in the unit 7 schedule to 09-10. It really is a new schedule but I do use the old version for formatting.

2) Section 1 . There was no typo. I had changed the question ( made it simpler) to match the answer rather than correct the typo in the answer. I just forgot I had done that.

AP Fluids Schedule ( Unit 7)

Here it is, the unit that is all wet (well not really gases are fluids too.) In ADDITION to schedule Read Notes on Archimedes by Tuesday 12/15. Also do Fluids Dynamics WS by
Monday 12/21
http://h1.ripway.com/DrCherdack/APUnit7Fluidsched-09-10.doc

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

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

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

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

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

http://h1.ripway.com/DrCherdack/Fluid%20Dynamics%20Worksheet%20.doc

AP Assignment for Unit 7 Fluids

Start our study of fluids off with the following readings : Text Section 13.1 then pages 378-80, then section 13.2 and then up through page 422. Answer conceptual questions 1,2,3,5,6 ( don't you hate those "know-it-alls" like Susan?). Also read Notes on Fluid Dynamics Sections 1 and 2.

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

Honors Assignment 2D Motion Continued

Complete AP Unit 2 Worksheets 1 and 2 and do problems 1 and 2 on Worksheet 3.

Use the table of components method we used in class and identify your angles carefully.

Magnitude is found by applying Pythagorean Theorem to the components ;
magnitude of C = sqrt( Cx^2 +Cy^2).

Direction is found from: angle from horizontal axis is angle = tan^-1 ( Cy/Cx).

Remember the velocity of A as seen from C is velocity of A with respect to B plus the velocity of B with respect to C. All addition is by components.


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

http://h1.ripway.com/DrCherdack/Unit_2_Worksheet_3.doc

Honors Section 1

I think we forgot to change the ship's velocity to 10 m/s in the components table. So lets just say the ship sped up and was now going 22 m/s when I threw the ball. Then our table will be correct. Change the sketch in your notes accordingly.

If you finished both AP sheets and the crate problem, all you have to do tonight is problems 2 and 3 on AP Unit 2 WS 3. See the next post to download it.

Weekend Assignment

I have been reading through your assignments. Thank you for sharing your thoughts. I will hold on to these reread them more than once I'm sure.

Honors Assignment

Do this problem and complete the AP worksheets if you can and think components.


http://h1.ripway.com/DrCherdack/2%20D%20Force%20Worksheet%201r1.doc

CANS!!!

Lets not prove folks they are right about you guys being self absorbed , inconsiderate, and all those others things we know ( sort of ) are not true. CANS !!!!

Governor's School Etc

Some of you should be thinking about outside opportunities like governor's school, Rutger's astrophysics program, science programs at Columbia, summers or weekends at Princetion Plasma Labs, etc. See me for more info

Vectors and Magnitude

Magnitude is just how "big" something is. The magnitude of a velocity is the speed; the magnitude of a displacement is its length; the strength of a force is its magnitude. It has same units and almost same meaning as the vector itself, just without the direction.

Honors Assignment.

Here is a an assignment aimed at helping you think about some mathematical operations. The second sheet is the real assignment but play with the first sheet for a while.Try moving the green and red blocks to help you see what each contains; ask yourself some other questions relating to multiplication and division. Also, look over the review sheet. If you have energy or time left try to finish the AP Unit 2 WS also.



http://h1.ripway.com/DrCherdack/Mathematical%20Operations.doc

http://h1.ripway.com/DrCherdack/Hnr%20Math%20Rev%2010-08.doc

http://h1.ripway.com/DrCherdack/Math%20Rev%20%20Hon%20Phys06-07.doc

AP Homework

Tomorrow, please tell me how long it took you to do the homework assignment for this past weekend and how much of it you were able to complete.

AP Power Sheet

When it asks for power for the cars find average power.

Finding power at beginning and end of an acceleration would also be interesting and you can do it if you assume all work is doing is changing KE and acceleration is uniform. [but you don't have to do these]

Honors Assignment

Reread Sect 3.1 -3.5 Answer question 7 ( think about your lab) and problems 9 and 10.

Also try this worksheet

http://h1.ripway.com/DrCherdack/Unit_2_worksheet_1.doc

AP Section 1

1) If you had a test where the MC answers were DBCAD or were about DBCAD (not AABBA) turn it back in. There are more points coming your way.

2) More cans NOW!!!

AP Rotational Energy WS

Hot off the press. In problem one, the radius of the wheel is 30 cm.

http://h1.ripway.com/DrCherdack/Rotational%20Energy%20Worksheet.doc

AP Homework Assignment

Here is the link to the Power sheet.

The rotational stuff will be up soon.

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

Food Drive

There are no food cans in 506 right now. Change that ASAP

Tuesday 12 /8 periods 5, 6, and 7

As you know, Mrs. Fern Wilson died last week. She was one the finest people and teachers I ever knew. I will try to attend her funeral periods 5,6,and 7 on Tuesday as a mark of the respect and affection I hold for her. If you knew her or know someone who did know her, please reserve a minute of thought for the passing of a wonderful person.

No email

Our email has been down since about 4PM Friday. What else is new?

Assignments for all including Topics

Honors Chapter 3 read sections 4,5 and 6 do problems 7,8,10

Honors and AP special assignment on grades

Topics show c^2 t-r^2 = c^2 t'^2 - r'^2

Honors Assignment 2D Motion

We now start the dreaded subject......... VECTORS!!! ( can't you just hear that evil, blood curdling laughter in the background) Read Chapter 3 Sections 1,2,3 Do problems 1,3,5.

Canned Food Drive

Donations have tailed off dramatically. Please think of others who are needy. You can do it

AP quiz and Lab Due Date

There will be a 1/2 period quiz tomorrow covering KE, PE, work, and losses. Not power or rotational energy. Section 1 ballistic pendulum lab is now due Friday - there is only so much whining I can stand.

AP and Honors Labs

A few of you continue to not turn in labs on time. Starting this week labs one week late lose a letter, labs more than 5 school days overdue will receive a zero. Returned labs to be resubmitted will be due no later than 6 school days after returned. No labs due before Thanksgiving will be accepted after this Thursday.