Question

part a
set the ball and the barrier about two feet apart on the table. grasp both ends of the ruler. push the ball using the center of the ruler so the ball rolls, hits the barrier, and rebounds from it. describe the motion of the ball as it moves.

Explanation:

1. Before collision (toward barrier): When the ruler pushes the ball, the ball starts moving in a straight - line path towards the barrier. Assuming the table surface is relatively smooth (minimal friction effects for the short distance), the ball will move with a roughly constant velocity (if the push force is applied briefly and the friction is negligible). The direction of motion is directly towards the barrier.
2. During collision (with barrier): When the ball hits the barrier, the barrier exerts a normal force on the ball (a force perpendicular to the surface of the barrier). This force causes the ball to decelerate rapidly as it comes into contact with the barrier. The direction of the ball's velocity changes as the normal force acts on it.
3. After collision (rebound): After hitting the barrier, the ball rebounds. If the collision is relatively elastic (and the barrier is rigid), the ball will move in a straight - line path away from the barrier. The direction of motion is opposite to the direction it was moving before the collision. The speed of the ball after the rebound may be slightly less than the speed before the collision due to energy losses (such as sound energy, heat energy from the collision, and friction with the table and air resistance). Also, if the table is level, the vertical motion of the ball (up - down) is negligible as the main motion is horizontal (along the table surface).

Answer:

• Before hitting the barrier: The ball moves in a straight - line path towards the barrier, likely with a relatively constant speed (if friction and other resistive forces are negligible) as it is pushed by the ruler.
• During the collision with the barrier: The ball decelerates rapidly as it interacts with the barrier, and the direction of its velocity begins to change.
• After rebounding from the barrier: The ball moves in a straight - line path away from the barrier (opposite to its initial direction of motion towards the barrier), with a speed that may be slightly reduced compared to its speed before the collision due to energy losses during the collision and resistive forces (friction, air resistance).