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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):
The ball's average velocity is 6 cm/sec. This value is obtained by taking the difference in distance covered (30 cm) and dividing it by the change in clock time (5 seconds)
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):
The final velocity must be 12 cm/sec. We can find this value by solving for x in the equation: 6 cm/sec = (0 cm/sec + x cm/sec)/2. We multiply both sides by 2 and get x = 12 cm/sec.
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By how much did its velocity therefore change?
answer/question/discussion: ->->->->->->->->->->->-> (start in the next line):
The ball's velocity therefore changed by 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):
The average rate the ball changed velocity with respect to clock time was 2.4 cm/sec/sec. We can find this value by dividing the change in average velocity by the change in clock time.
12 cm/sec / 5 sec = 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):
A graph of the ball's velocity vs. clock time would be a straight line going from the origin, up and right. The slope would be positive and the equation for the line representing this graph would be y = 6x
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15 minutes
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2/28 11:50
&#Very good responses. Let me know if you have questions. &#