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Phy 121
Your 'cq_1_03.1' 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_03.1_labelMessages.txt **
The problem:
A ball starts with velocity 0 and accelerates uniformly down a ramp of length 30 cm, covering the distance in 5 seconds.
What is its average velocity?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
vAve = 30 cm / 5 sec = 6 cm/sec
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If the acceleration of the ball is uniform then its average velocity is equal to the average of its initial and final velocities.
You know its average velocity, and you know the initial velocity is zero.
What therefore must be the final velocity?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
12 cm/sec
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By how much did its velocity therefore change?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
6 cm/sec
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If the velocity started at 0 and increased to 12 cm/s, the change in velocity is more than 6 cm/s.
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You don't say how you reasoned this out.
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At what average rate did its velocity change with respect to clock time?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
average rate = (12 cm/sec - 6 cm/sec) / 5 sec = 6/5 cm/sec^2
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The velocity didn't start at 6 cm/s.
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What would a graph of its velocity vs. clock time look like? Give the best description you can.
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The graph would be increasing at a constant rate. Two points on the graph would be (0, 0) and (5, 12). The slope would be 6/5.
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The slope between (0, 0) and (5, 12) is not 6/5.
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*#&!
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You're doing most things right, but you are making some common errors.
&#Please see my notes and submit a copy of this document with revisions, comments 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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