course phy 201

9-11 9:11 AM

The problem:vvvv

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: 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: 12 cm/sec

• By how much did its velocity therefore change?

answer/question/discussion: It increased by 12 cm/ sec from zero. (I think)

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

answer/question/discussion: 2.4 cm/sec^2

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

answer/question/discussion: Increasing at an increasing rate.