Monday, March 31, 2008
Thursday, March 27, 2008
AP Test Review
We will review the B6 MC AP test on Monday. Make sure you bring it with you. Also bring the FR parts just in case we move quickly
Wednesday, March 26, 2008
Tuesday, March 25, 2008
All Students Labs
I have posted numerous explanations, sample calculations and other information on many labs. If your submissions are later than those posts, your report must show you have read those posts. It is extremely wasteful of my time and yours for you to submit reports containing errors and omissions already addressed in these posts.
Starting tomorrow, you will not get a second, or in some cases a third or fourth chance to correct a lab with errors already addressed in a post.
Honors and Mathematics Homework
In preparation for the quiz tomorrow:
Do the practice problems attached to your schedule. Note the first problem has NO NUMBERS ( other than kc) . Also, make sure you understand how to calculate field from Flux = Q/epsilon ( Gauss Law) and how a charges respond to a nearby charged object, what grounding allows to happen, etc.
Monday, March 24, 2008
AP FR
You don't deserve this, but here is a solution set to FR2005. Compare your work to it and see me if you can't get it.
FR2005Solns0001.pdf
FR2005Solns0001.pdf
Sunday, March 23, 2008
AP Schedule for Magnetics
Here are links for schedule etc. for Unit 13 Magnetics:
APUnit13Magsched08.doc
Unit13Worksheet1.DOC
Unit13Worksheet2.doc
Unit13ProblemSheet.doc
APUnit13Magsched08.doc
Unit13Worksheet1.DOC
Unit13Worksheet2.doc
Unit13ProblemSheet.doc
Friday, March 21, 2008
All Students Revised Notes on Electrostatics
Here is a new revision to those notes. I tried to clear up some points on electric potential and charge concentrations. Also, there are some example problems that probably only the mathematical class has seen. I suggest you download these, read them and replace your older notes with these.
NotesElectrostatic3-08r1.doc
NotesElectrostatic3-08r1.doc
Monday, March 17, 2008
Electrostatics and current Web sites
Here is the link for the sites we used in computer labs last week:
http://www.hazelwood.k12.mo.us/~grichert/sciweb/electric.htm
http://www.hazelwood.k12.mo.us/~grichert/sciweb/electric.htm
[AP students look over the circuits links, you probably need the practice and then go back and do the electrostatics]
All students go to the electrostatics physlets and do all 4 but present the solution for number 4 (find the mass of the particle) explaining how you did it. For AP its 20 points extra credit. For honors it is an assignment and it will replace your lowest lab grade from other labs. For mathematical it is all that plus 30 points of extra credit. Try to solve it on your own. If you can't, here are some hints, but don't read them all at once. Try solving it with as few hints as possible. Q is given in the text.
The time is given ( note it is in milliseconds). The location is given in yellow when you click on a position. The field, E, is .5 N/C where ever the stripes are shown and zero elsewhere. The difference between the kinetic energy before and after the field = M/2( vi squared - vf squared) the field is equal to work done by the field. This work is force x distance = Q E dist. Write this as an equation, then manipulate the quantities and come up with an equation for M.
You can find dist by clicking on the first line and then the last line and noting the change in location. You can find vi by putting the particle before the field by clicking on the particle, noting x and t, then by starting and pausing again before it enters the field and noting x and t again. You now know delta x and delta t before the field, so you can find vi. You can do the same after the field.
Wednesday, March 12, 2008
Electrostatics Lab
The majority of you missed several points:
1) You were supposed to use mobility of electrons to explain the pith ball's attraction to the glass rod. This could be done in two ways: a) ball was negative because it gathered some excess mobile electrons from the black rod earlier or b) ball was neutral but some electrons on ball moved to the side closer to the glass rod so the ball had a charge distribution with some excess negative charge closer to the positive rod than the excess positive on the opposite side of the ball.
2) You were asked to explain what happened in observations D1 and D2 not just describe them.
3) Many of you said your finger in D led to a positive charge on the scope, allowing electrons to escape. This is correct. But then in your next answer you said it neutralized the scope in B and D. This is true for B but clearly not D. In both B and D it did serve as a path for electrons to leave the scope, but in D this led to a charged, not neutral scope.
4) You were asked to compare the charge on the object causing the charge with the charge on the object being charged. This is a general question and does not refer to a particular experiment. Thus, negative and positive are not possible answers since it is not known if the object doing the charging is positively or negatively charged. The correct answers are: for conduction, the object doing the charging and object becoming charged have same charge; for induced charge, the objects will have opposite charges.
5) For the rod and two spheres: the two spheres are not grounded and the rod does not touch sphere A. Therefore the total number of electrons on the two spheres is equal to the total number of protons. However the negative rod near A will push some electrons onto B. If you move A and B apart before the rod is removed from the vicinity of A, then B will retain the excess electrons and A will be missing the same number, so A is + and B is -.
All Students Labs
If you have a lab that should be resubmitted you must do so by 3/24/08; the day we return from break.
If you have a lab that says see me, it does not mean that you must note my existence by visual evidence. It means you must meet with me before you prepare your re submital.
If you have a lab that says see me, it does not mean that you must note my existence by visual evidence. It means you must meet with me before you prepare your re submital.
Monday, March 10, 2008
Thursday, March 6, 2008
AP Tuesday March 11
Bring in the Unit 12 problem sheet to do in class.
Also try doing the extra problems for 15 points extra credit
Unit12ExtraProblems.doc
Also try doing the extra problems for 15 points extra credit
Unit12ExtraProblems.doc
Honors and Mathematical Homework
All waves and sound homework is due. Make sure you turni it in befoer Friday PM.
Wednesday, March 5, 2008
Tuesday March 11
Now here is what you have really been waiting for: I will not be in school from 3rd period through 8th period on Tuesday March 11, because I will be taking all the really good guys ( i.e. the physics club) to see how electricity is generated at a real live power plant.
Please bring in worksheets (already on your schedule for Honors and to be posted soon for AP and mathematical, so you will not be idle ( I know what you are really like).
Honors Unit 10 Schedule
Here it is: what you all have been waiting breathlessly for [ I can dream can't I?]
HonorsUnit10ElecStat-08-.doc
Unit10Worksheet1.doc
Unit10Worksheet2.doc
Unit10Worksheet3.doc
HonorsUnit10ElecStat-08-.doc
Unit10Worksheet1.doc
Unit10Worksheet2.doc
Unit10Worksheet3.doc
Study Groups
1) I will convene an informal study group on waves tomorrow. All are welcome I would like to make this a regular weekly event if enough are interested and we can pick a day based on maximum convenience. Email me if interested in being part of this group next week and beyond.
2) Where are your reports? One per person per unit is required.
Quizzes
I have faced the fact that 21 minutes is less than 41 minutes which was already inadequate. There will be mini type quizzes tomorrow and a more serious one ( but not a full blown test) on Friday for mathematical. I will figure out some way to get even with you honors guys later.
Tuesday, March 4, 2008
Physics Club Trip
All those going on the physics club trip next Tuesday need to pick up a permission slip in 506. They are on the rack by the door, in an orange folder.
Honors Quiz
Due to lost class time and other problems the quiz will be no earlier than Thursday. Stay posted for news of any changes beyond this, but don't count on them
Monday, March 3, 2008
Honors and Mathematical Class Quizzes
Yes I know, you have HSPAs. Yes I know you will be terribly fatigued and stressed out. Yes I know how hard you all work on all your courses all the time. However, we are still having quizzes on standing waves, resonance and sound on Wednesday. They will be real type quizzes, not the scantron/questions on the screen ones. However, they will be suitable for the short periods.
For Mathematical, there will also be a more comprehensive quiz on Friday since we already did a lab this week, we can review before the quiz.
Honors will be starting a new Unit on electricity on Friday. Anyone who wants to bring in an instrument can do so Thursday. We'll analyze the sounds they make.
Good Luck on your HSPAs,
Dr. Cherdack
For Mathematical, there will also be a more comprehensive quiz on Friday since we already did a lab this week, we can review before the quiz.
Honors will be starting a new Unit on electricity on Friday. Anyone who wants to bring in an instrument can do so Thursday. We'll analyze the sounds they make.
Good Luck on your HSPAs,
Dr. Cherdack
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