Question

A 100 g iron ball having velocity 10 m/s collides with a wall at an angle 30° and rebounds with the same angle. If the period of contact between the ball and wall is 0.1 second, then the force experienced by the wall is

• A. 10 N
• B. 100 N
• C. 1.0 N
• D. 0.1 N

Answer 1

Answer: (A)

10 N

Answer 2

During collision of ball with the wall horizontal momentum changes (vertical momentum remains constant)

$\therefore F = \frac{\text{Change in horizontal momentum }}{\text{Time of contact}}$

$= \frac{2P\cos\theta}{0.1} = \frac{2mv\cos\theta}{0.1} = \frac{2 \times 0.1 \times 10 \times \cos 60{^\circ}}{0.1} = 10\mspace{6mu} N$