Phy 201
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: Average velocity is found by taking the change in position over the change in time. In this case, it would be 30cm/ 5sec-0secs. This gives an average velocity of 6cm/sec
• 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: If the average velocity is equal to the average of the initial velocity (0) and the final velocity, the final velocity must be twice the average velocity. This would be 12 cm/sec.
• By how much did its velocity therefore change?
answer/question/discussion: The velocity changed by 12 cm/sec over the whole interval since the initial velocity was 0 and and 6cm/sec over the second interval since the average velocity is 6cm/sec.
• At what average rate did its velocity change with respect to clock time?
answer/question/discussion: To find this you take the final velocity and divide it by the total number of seconds. This would give you 12cm/sec/ 5 sec which is 2.4cm/sec/sec. This means that each second the velocity of the system increased by 2.4 sec on average.
• What would a graph of its velocity vs. clock time look like? Give the best description you can.
answer/question/discussion: The graph would be linear with a slope of 2.4cm/sec. The y intercept would b at 0 corresponding 0 velocity with 0 seconds. The graph would be positive and would have clock time on the x axis and velocity on the y axis.
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15 minutes
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&#Very good responses. Let me know if you have questions. &#