Welcome to blog help for PHY 122! Here's how it works.
For each homework question and lab report we will make a post, this will probably contain a few tips on what the problems are about and how to solve them. If you are stuck on something then instead of emailing us directly you should post a comment in reply to the relevant post. We will try to guide you through tough points and help you understand the problems and the concepts behind them.
Tuesday, September 28, 2010
Practice Midterm Exam
This thread is for discussion of problems in the practice midterm exam, which is posted in Blackboard in Course Documents.
8 comments:
Vito
said...
Im having trouble with number 2 on the exam. I can't figure out how to get the answer. I do (10e-6)(-1.6e-19)/(.05^2) to find the x part, and then I lose what to do with the y components. help!
Do the two corners seprately. So from the lower left corner, the magnitude of the force is (9E9)*(10E-6)*(1.6E-19)/(0.0707^2) and it is directed down and to the left. Force from lower right corner has same magnitude, is directed up and to the left. Then take the sum of those two vectors. It looks like you're trying to take x and y components of displacement to determine the x and y components of force, but that doesn't work.
I have questions about the actual test (Sorry I'm posting here, but I wasn't sure where else to post these questions). I know we're allowed to bring a sheet of notes to the test, but I want to make sure I know what's allowed before I start writing it up. Are we only allowed to write formulas or can we have worked out problems as well? Also, does it matter if it is typed or hand written? Finally, do we get to keep the note sheet after the test, or do you collect them?
For question 15 on the practice exam, The oscilloscope that recorded this trace was set to 1 msec/division horizontal and 0.1 Volts/division vertical.What is the frequency of the signal that was being measured?
Please refer to the picture.
I have no idea where to start with this question, :( I just simply know that Frq(Hz)=1/period (s)
8 comments:
Im having trouble with number 2 on the exam. I can't figure out how to get the answer. I do
(10e-6)(-1.6e-19)/(.05^2) to find the x part, and then I lose what to do with the y components. help!
Do the two corners seprately. So from the lower left corner, the magnitude of the force is (9E9)*(10E-6)*(1.6E-19)/(0.0707^2) and it is directed down and to the left. Force from lower right corner has same magnitude, is directed up and to the left. Then take the sum of those two vectors.
It looks like you're trying to take x and y components of displacement to determine the x and y components of force, but that doesn't work.
I have questions about the actual test (Sorry I'm posting here, but I wasn't sure where else to post these questions). I know we're allowed to bring a sheet of notes to the test, but I want to make sure I know what's allowed before I start writing it up. Are we only allowed to write formulas or can we have worked out problems as well? Also, does it matter if it is typed or hand written? Finally, do we get to keep the note sheet after the test, or do you collect them?
You can write anything you want in any way that you want. You can keep your notes, and the written exam paper when you leave the exam.
Hi,
For question 15 on the practice exam,
The oscilloscope that recorded this trace was set to 1 msec/division horizontal and 0.1 Volts/division vertical.What is the frequency of the signal that was being measured?
Please refer to the picture.
I have no idea where to start with this question, :( I just simply know that Frq(Hz)=1/period (s)
Please help.
dont exactly get what is meant from infinity in number 6. How do you get a finite number if its infinite distance away
My one and only calculator is a Ti-83 plus graphing calculator.
Is that okay for the exam?
Please let me know.
Practice Exam Q15. Have a look at the writeups for lab #2, and at the 3rd clicker question of Sept. 23 lecture.
Practice Exam Q6. Review section 16.2 in the textbook, and/or latter part of September 7 lecture.
Calculator: Any calculator is OK: graphing, symbolic, whatever you want. Except you can't use the calculator app of a smartphone or a laptop computer.
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