1. Recitation 5

2. Problem 25
25. (II) A tennis ball of mass m=0.060kg and speed v=25m/s strikes a wall at a 45° angle and rebounds with the same speed at 45° (Fig. 9–38). What is the impulse (magnitude and direction) given to the ball?

3. Problem 56
56. (II) Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Initially ball A is moving upward along the y axis at 2.0m/s, and ball B is moving to the right along the x axis with speed 3.7m/s. After the collision (assumed elastic), the second ball is moving along the positive y axis (Fig. 9–43). What is the final -direction of ball A, and what are the speeds of the two balls?

4. Problem 50
50.(II) A pendulum consists of a mass M hanging at the bottom end of a massless rod of length 𝑙, which has a frictionless pivot at its top end. A mass m, moving as shown in Fig. 9–42 with velocity 𝑣 impacts M and becomes embedded. What is the smallest value of 𝑣 sufficient to cause the pendulum (with embedded mass m) to swing clear over the top of its arc?