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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.
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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: ->->->->->->->->->->->-> :
The average velocity is vAve= ‘ds/ ‘dt= 20cm/2s= 10cm/s
The final velocity is: vAve= (vf+v0)/2 = 10cm/s=(vf+0)/2= 20cm/s=vf
The acceleration is: ‘dv/’dt= (20cm/s-0cm/s)/2=10cm/s/s
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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: ->->->->->->->->->->->-> :
3 percent longer would make the seconds 2.06 s.
Therefore the vAve= 20cm/2.06=9.7cm/s
The vf would = 9.7cm/s=(vf+0)/2.06=19.98cm/s
Your vf should be 19.4 cm/s.
vAve = (vf + v0) / 2, not (vf + v0) / `dt.
The acceleration would be= (19.98-0)/2=9.99cm/s/s
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• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
The percent error would be 3 % for all of them.
That's not the case. You should actually calculate your percent errors.
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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: ->->->->->->->->->->->-> :
This is because both of these variables are found by knowing the ‘dt and if the ‘dt was off by 3 seconds then the other figures will be as well.
Good reasoning but you've overlooked something important.
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• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
They are not.
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10 minutes
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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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