QUIZ: to turn in

2. QUIZ: to turn in Analyze the motion in the loop.mov video using Logger Pro. Note that the ball bearing has a mass of 28 grams and the plastic track has a radius of about 10 cm. Since the velocity is not constant in x or y, you can’t use a fit line to estimate velocity. Change your graph to x-velocity and use the data point that corresponds to the appropriate frame. 1. Draw two free-body diagrams: one for when the ball is at the top of the loop and another for when the ball is at the bottom. 2. What is the normal force on the ball as it enters the loop and begins circular motion? Hint: it’s not equal to the ball’s weight. 3. What is the normal force on the ball at the top of the loop? 4. If you were riding on this “roller coaster”, where would you feel heavier: at the top or bottom?

3. A 5.0 g coin is placed 15 cm from the center of a turntable. The coin’s coefficients of friction with the table are µs=0.80 and µk=0.50. The turntable takes 2.5 seconds to get spinning at 78 rpm. * What is the tangential component of the coin’s acceleration? * What is the maximum overall acceleration the coin can take before it slides off? * At what time does the coin slide off?

5. A 49 g rubber ball is dropped from a height of 2.1 m and rebounds to two-thirds of its initial height. What are the magnitude and direction of the impulse that the floor exerts on the ball? If the impact has the profile shown below, what maximum force does the floor exert on the ball?