A 0.050 kg tennis ball initially moving at 15 m/s toward you. You return the shot and plot the force exerted on the ball (shown right). What is the velocity of the return shot?

To practice problem-solving strategy 10.1 for energy conservation problems. a sled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slides a distance d1 down the slope and then covers the distance d2 along the horizontal terrain before stopping. find the coefficient of kinetic friction μk between the sled and the ground, assuming that it is constant throughout the trip.