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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.
** CQ_1_09.1_labelMessages **
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: ->->->->->->->->->->->-> :
20cm / 2s = 10cm/s = Vave
Vf = 2*Vave = 20cm/sec
a = 20cm/s / 2 s = 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: ->->->->->->->->->->->-> :
20cm / 2.06s = 9.71cm/s = vave
Vf = 19.42cm/s
a = 9.43cm/s^2
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What is the percent error in each?
answer/question/discussion: ->->->->->->->->->->->-> :
.03
.06
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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: ->->->->->->->->->->->-> :
n/a
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If the percent errors are different explain why it must be so.
answer/question/discussion: ->->->->->->->->->->->-> :
The % error for a is twice that of vf. That makes sense because a is of higher magnitude than v
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@&
The main point is that in calculating a you divide by `dt twice, each time contributing about a 3% error.
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&#Your work looks good. See my notes. Let me know if you have any questions. &#