A goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goalkeeper to
- Adecrease the rate of change of momentum
- Bexert large force on the ball
- Cincrease the force exerted by the ball on hands
- DMore than one of the above
- ENone of the above
Show answer and explanation
Correct answer: (a) decrease the rate of change of momentum
Explanation
Pulling the hands back increases the time over which the ball is stopped.
By Newton's second law, force equals the rate of change of momentum; a longer time lowers this rate and the force on the hands.
This decreases the rate of change of momentum, protecting the goalkeeper from injury.