#$&*
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: ->->->->->->->->->->->-> :
`ds = 20cm
`dt = 2sec
V = `ds / `dt
V_avg = 10cm/s
Vf = 10cm/s * 2sec = 20cm/s
A = 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: ->->->->->->->->->->->-> :
2 sec * .03 = .06
V = `ds / `dt
V_avg = 20cm / 2.06sec
V_Avg = 9.70873m/s
Vf = 19.4174m/s
A = 9.70873cm/s^2
@& It looks like you obtained this last result using a time interval of 2 sec, not the new time interval.*@
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• What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
vf error = 19.4174 - 20 / 20 * 100% = 2.9%
acceleration error = 9.70873 - 10 / 10 = 2.9%
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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: ->->->->->->->->->->->-> :
Yes, the percent error is the same because the error was only introduced in one value that was utilized in calculating both velocity and acceleration.
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• If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
They are not different.
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15 minutes
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@& Again you should correct your error. Simple error, easy to correct, but valuable lesson here.
Note that the correction will affect your subsequent answers, so be sure to correct them as well.
&#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. &#
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