#$&*
Phy 121
Your 'cq_1_09.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
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A ball accelerates uniformly as it rolls 20 cm down a ramp, starting from rest, in 2 seconds.
What are its average velocity, final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> :
vAve='ds/'dt=20cm/2s=10cm/s
vf=2*vAve=2*10cm/s=20cm/s also 'dv
aAve='dv/'dt=(20cm/s)/2s=10cm/s^2
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If the time interval is in error so that it is 3% longer than the actual time interval, then what are the actual values of
the final velocity and acceleration?
answer/question/discussion: ->->->->->->->->->->->-> :
t=2s*.97=1.94
vAve=10cm/s*1.03=10.30cm/s
aAve=20cm/s^2*1.03=20.6cm/s^2
@& vAve will be close to this.
However you should calculate vAve and aAve based on your correct 1.94 s interval, not on the assumption that both will be 3% greater than before. That will turn out not to have been the case.*@
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What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
3%
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If the percent error is the same for both velocity and acceleration, explain why this must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
The time is used in both calculations.
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If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
#$&*
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30 min
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@& You got your percent error by assuming what your percent error would be.
See my note. It should be clear what needs to be done, and I don't think you'll have trouble doing it.
&#Please see my notes and, unless my notes indicate that revision is optional, 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.
If my notes indicate that revision is optional, use your own judgement as to whether a revision will benefit you. &#