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Phy 231
Your 'cq_1_09.1' 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: ->->->->->->->->->->->-> :
x-x0 = 0.5 * (v0 + vf) *t
20 = 0.5 * (0 + vf) * 2
vf = 20 m/s
v_Ave = (0 + 20)/2 = 10 m/s
x-x0 = v0 * t + 0.5 * a * t^2
20 = 0 + 0.5 * a * 2^2
a = 10 m/s^2
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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: ->->->->->->->->->->->-> :
x-x0 = 0.5 * (v0 + vf) *t
20 = 0.5 * (0 + vf) * 2.06
vf = 19.42 m/s
x-x0 = v0 * t + 0.5 * a * t^2
20 = 0 + 0.5 * a * 2.06^2
a = 9.43 m/s^2
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What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
velocity = ((20-19.42)/19.42) * 100 = 3%
accel = ((10 - 9.43)/9.43) * 100 = 6%
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If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
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If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
The percent errors are different because the velocity depends on t and
acceleration depends on t^2.
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*#&!
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See any notes I might have inserted into your document, and before looking at the link below see if you can modify your solutions. If there are no notes, this does not mean that your solution is completely correct.
Then please compare your old and new solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified.If your solution is completely consistent with the given solution, you need do nothing further with this problem.
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