Final answer:
In a collision with a wall, the ball and the wall exert impulses simultaneously as per Newton's third law of motion, where action and reaction are equal and opposite.
Step-by-step explanation:
In a collision with a wall, both the wall and the ball exert impulses on each other simultaneously. According to Newton's third law, for every action, there is an equal and opposite reaction. When a ball strikes a wall, it exerts a force in the +x direction (assuming motion towards the wall is positive), and at the same moment, the wall exerts an equal force on the ball in the -x direction. These forces occur at the same time, resulting in an impulse being applied on each other that is equal in magnitude but opposite in direction.
This concept is demonstrated in the collision of a ball with a wall where the ball changes its x-component of momentum upon impact. The change in momentum, which is proportional to the velocity, is directly related to the impulse caused by the wall's force on the ball, and vice versa. Consequently, the momentum of the ball in the direction normal to the wall's surface is reversed, which indicates the impulse provided by the wall.