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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):
The coordinates: t=0sec, s=0sec and t=5sec, s=30cm are implied.
Using the formula, vAve = 'ds /'dt, I calculated vAve = 30cm/5sec = 6cm/s
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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):
If vAve = (v0 +vf) / 2, then vf = 2vAve - v0 or since v0=0 then vf=2*vAve.
vf= 2*6cm/sec
vf= 12cm/sec
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By how much did its velocity therefore change?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
'dv= 12cm/s - 0cm/s
'dv = 12 cm /sec
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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):
aAve= 12cm/s / 5sec = 2.4cm/s/sec
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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 shows a linear line increasing with aa slope of 2.4.
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The slope has units. Otherwise, fine.
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Very good, but do check out my one note, just above this one.
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