Physics helps us to predict what happens when two objects collide and exert
equal-but-opposite force on one another. Our example: a ball striking a wall of
infinite mass and bouncing back in the opposite direction.
Physics helps us to predict what happens when two objects collide and exert
equal-but-opposite force on one another. Our example: a ball striking a wall of
infinite mass and bouncing back in the opposite direction.
The ball has an original vector momentum po = mvo to the right. When the ball contacts the wall, an action-reaction pair of forces is exerted on the wall and the ball as shown; these are equal in magnitude but opposite in direction, and they are also changing with time as the ball compresses on approach and relaxes on bounce. The forces, acting over time of contact, accelerate both the ball (it slows down, stops, and reverses direction) and the wall (in principle it goes from being at rest to moving to the right as a result of being hit).
However, because the wall is of much larger mass than the ball, the acceleration of the ball is much more noticeable than the acceleration of the wall.
