Please help!

57.

57. || A rubber ball bounces. We'd like to understand how the ball bounces. a. A rubber ball has been dropped and is bouncing off the floor. Draw a motion diagram of the ball during the brief time interval that it is in contact with the floor. Show 4 or 5 frames as the ball compresses, then another 4 or 5 frames as it expands. What is the direction of 3 during each of these parts of the motion? b. Draw a picture of the ball in contact with the floor and identify all forces acting on the ball. c. Draw a free-body diagram of the ball during its contact with the ground. Is there a net force acting on the ball? If so. in which direction? d. Write a paragraph in which you describe what you learned from parts a to c and in which you answer the question: How does a ball bounce? 19. II Zach, whose mass is 80 kg, is in an elevator descending at 10 ml 5. The elevator takes 3.0 s to brake to a stop at the first oor. a. What is Zach's weight before the elevator starts braking? b. What is Zach's weight while the elevator is braking? 21. | What thrust does a 200 g model rocket need in order to have a vertical acceleration of 10 m/s a. On earth? b. On the moon, where g = 1.62 m/s??37. II A 2.0 kg object initially at rest at the origin is subjected to the time-varying force shown in FIGURE P637. What is the object's velocity at I = 4 s? 0 1(5) FIGURE P637 0 l 2 3 4 39. || The 1000 kg steel beam in FIGURE P639 is supported by two ropes. What is the tension in each? FIGURE P639