Final answer:
The tennis ball's change in momentum upon striking and bouncing off the wall is matched by an equal and opposite change in the wall's momentum, per Newton's third law, thus ensuring momentum conservation. Some kinetic energy is lost in the process as it is transformed into other forms like heat or sound.
Step-by-step explanation:
When a tennis ball strikes a wall with an initial speed of 15 m/s and then bounces off with a slightly reduced speed of 14 m/s, two important physical processes occur. First, the ball's momentum changes, which, according to Newton's third law, means the wall must exert an equal and opposite force on the ball, hence changing the wall's momentum to conserve overall momentum. Since the wall is much more massive than the tennis ball, its motion is negligible, but the momentum transfer still occurs. Second, considering the ball's loss of speed, some of the ball's kinetic energy is converted into other forms, like heat and sound, during the impact with the wall.
To calculate the force on the wall, we can use Newton's second law and recognize that the force exerted by the wall on the ball is equal in magnitude and opposite in direction to the force the ball exerts on the wall. Given the ball's mass and change in velocity (which includes direction), we can determine the change in momentum, and with the time between hits, we can find the average force exerted by the ball on the wall. Kinetic energy loss can be calculated by comparing the kinetic energies before and after the collision, with the difference representing the energy that was not retained as kinetic.