Final answer:
If the bat remained still when hit by the ball, Newton's third law would result in the bat exerting an equal and opposite force on the ball, with different effects based on the point of contact on the bat.
Step-by-step explanation:
If a person did not move the bat and kept it still when the ball hit it, the ball would exert a force on the bat, and according to Newton's third law of motion, the bat would exert an equal and opposite force back on the ball. This interaction between the ball and the bat could result in a variety of outcomes depending on where the ball hits the bat. For instance, if the ball hits the sweet spot or percussion point of the bat, there would be less force exerted on the person's hands holding the bat and minimal vibration. However, if the ball makes contact with the bat at a different point, it could cause more vibration and potentially damage the bat, as was often the case with Mariano Rivera's cutter pitches breaking bats.
Furthermore, if the ball had collided with the floor and stopped without bouncing, the ball's change of momentum would be based on the principle that a force during a collision results in a change of momentum. The momentum change would be contingent on the amount of force exerted over the time of impact as demonstrated in the baseball collision example where a 150-g baseball undergoes a force calculation after being struck by a bat.