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Phy 231
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):
average velocity is change in distance over time
vAve= ds/dt = 30cm/5sec = 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):
vAve = (vf-vo)/2
vAve*2=vf (vo=0)
vf=12cm/sec
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By how much did its velocity therefore change?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
change in velocity = final velocity - initial
dv= vf-vo = 12-0 = 12cm/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):
average rate of change of velocity = acceleration = (vf-vo)/dt = 12(cm/sec)/5sec = 2.4 cm/sec/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):
It would be a curve, starting at (0,0) and ending at (30,5). A straight line linking the two positions would have a slope of ds/dt = 30/5 = 6 cm/sec (also vAve)
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That describes a graph of position vs. clock time.
Can you describe the graph of velocity vs. clock time?
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