Phy 201
Your 'cq_1_9.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A ball accelerates uniformly as it rolls 20 cm down a ramp, starting from rest, in 2 seconds.
• What are its average velocity, final velocity and acceleration?
answer/question/discussion: vAVE = 10 cm/s (`ds / `dt)
vf = 20 since vAVE also = (vf + v0) / 2
Thus, acceleration is also 10 cm/s.
• If the time interval is in error so that it is 3% longer than the actual time interval, then what are the actual values of the final velocity and acceleration?
answer/question/discussion: vAVE = `ds / `dt = 20 / 2.06 = 9.71
vf would then be 9.71 = (vf + 0) / 2.06 = 20.0026 cm/s
Slight but significant error here:
vAve = (vf + v0) / 2, not (vf + v0) / `dt.
acceleration then = 20.0026 / 2.06 = 9.71
• What is the percent error in each?
answer/question/discussion: The percent error is .29 in velocity and acceleration.
• If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: This has to be so because they are proportional and rely on each other. In order to find a you must use vAVE.
• If the percent errors are different explain why it must be so.
answer/question/discussion:
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20 minutes
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&#At least part of your solution does not agree with the solution and comments given at the link below. You should view the solution at that link and self-critique as indicated there.
Solution
This link also expands on these topics and alerts you to many of the common errors made by students in the first part of this course. &#