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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.
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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 = ‘ds / ‘dt
vAve = 30 cm / 5 sec
vAve = 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 = (vInitial + vFinal) / 2
6cm/sec = (0cm/sec + vFinal) / 2
6cm/sec = vFinal / 2
6cm/sec * 2 = vFinal
vFinal = 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 = vFinal - vInitial
Change in velocity = 12cm/sec - 0cm/sec
Change in velocity = 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):
Average rate = change in velocity / change in time
Average rate = 12 cm/sec / 5 sec
Average rate = 2.4 cm/sec^2
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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 begin at (0,0) and go to (12,5) in a straight line. It would be increasing at a constant rate.
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&#Your work looks very good. Let me know if you have any questions. &#