cq_1_031

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 down a ramp of length 30 cm, covering the distance in 5 seconds.

What is its average velocity?

vAve = `ds/`dt = 30cm/5s = 6cm/s

If the acceleration of the ball is uniform then its average velocity is equal to the average of its initial and final velocities.

If I were to graph this, I would mark the acceleration along the y (vertical) axis and mark time along the x (horizontal) axis. The graph would show a straight, horizontal line since the acceleration is uniform and the average velocity is equal to the average of the ball's initial & final velocities.

You know its average velocity, and you know the initial velocity is zero. What therefore must be the final velocity?

vf = 2vAve - v0 = 2(6) - 0 = 12cm/s

By how much did its velocity therefore change?

12cm/s

At what average rate did its velocity change with respect to clock time?

a = `dv/`dt = (12cm/s)/(5s) = 2.4cm/s^2

What would a graph of its velocity vs. clock time look like? Give the best description you can.

A graph of the ball's velocity vs. clock time would look like a diagonal line (increasing at a constant rate) as the velocity is directly proportional to the clock time.

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20 min.

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Please respond relative to goal of C.

&#Very good responses. Let me know if you have questions. &#