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phy 201
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.
** CQ_1_09.1_labelMessages **
A ball accelerates uniformly as it rolls 20 m down a ramp, starting from rest, in 2 seconds.
• What are its average velocity, final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> :
ds = 20cm
Vi= 0
Vf= 10m/s
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It isn't clear how you got v_f = 10 m/s, but this is not correct.
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T= 2sec
Vave = 5m/s
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If the average velocity was 5 m/s then the ball would require 4 seconds to travel 20 m. This is clearly not the case.
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A = 2.5m/s^2
Ds = (vo+vf)/2 * dt
20 = (VF)/2 * 2
10=vf
100=2(a)(20cm)
100=40a
=2.5m/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: ->->->->->->->->->->->-> :
t= 1.94sec
vf= 20.6m/s
a= 10.6m/s^2
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• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
3%
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10.6 m/s differs from 10 m/s by 6%, not by 3%.
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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: ->->->->->->->->->->->-> :
the same change in percent from the time interval
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• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
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20min
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Much of your reasoning is correct, but you have to serious errors, which should however be easy to fix.
&#Please see my notes and submit a copy of this document with revisions and/or questions, and mark your insertions with &&&& (please mark each insertion at the beginning and at the end).
Be sure to include the entire document, including my notes. &#
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