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MGR PostLab

Acceleration and Velocity on the Physics Merry-Go-Round

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Give all numerical answers to 2 significant figures.  Use SI units unless instructed otherwise.

1. The movie clip above runs at 15 frames per second. Find the period of rotation of the MGR in seconds. (Note that you can advance the clip frame-by-frame.)  Describe your method.

The following questions deal with the rider in the white jeans.

2. The diameter of the plank is 12 feet. Estimate the distance from the rider to the center of the MGR in meters.  Describe your method.

For the following, assume the point of view of the camera (an inertial observer on the ground).

3. How fast is the tennis ball moving tangential to the circular path at the instant it leaves the thrower's hand? Describe how you found your answer.

4. Calculate the centripetal acceleration of the rider. Give your answer in units of g, the Earth's gravitational field.

5. How fast is the tennis ball moving radially toward the wastebasket at the instant the ball leaves the thrower's hand? Describe how you found your answer. (To simplify this, assume that the ball would have landed in the wastebasket were it not for the rotation of the thrower.)

6. How fast is the tennis ball moving vertically at the instant the ball leaves the thrower's hand? Describe how you found your answer.

7. If the initial velocity vector of the ball were projected onto a horizontal plane, what angle would the projection* make with the MGR at the instant the ball is released? Describe how you found your answer.

*The diagram may help to show what a projection is. AC is the projection of vector AB onto line L.

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