TeXes Science Practice Test

When a billiard ball collides with the edge of the table, the angle at which it rebounds is equal to which angle?

1. The angle of approach

2. The angle of reflection

3. The angle of incidence

4. The angle of deflection

The correct answer is: The angle of incidence

The angle at which the billiard ball rebounds from the edge of the table is known as the angle of incidence. This term refers to the angle formed between the incoming path of the ball and the line perpendicular to the edge (the normal line) at the point of collision. In the context of a collision, when the billiard ball approaches the edge of the table, it meets the edge at a specific angle relative to this normal line. When it strikes the edge, the law of reflection states that the angle of incidence will be equal to the angle of reflection. This means that after the collision, the ball will rebound at an angle that matches the initial angle of approach to the edge, relative to that same normal line. Thus, the correct relationship lies between the angle of incidence and the angle of reflection, confirming that the angle at which it rebounds directly correlates to the angle of incidence.