Question

A goalkeeper in football game pulls his hands backwards after holding the ball shot at the goal. This enables the goal keeper to

• A. exert larger force on the ball
• B. reduce the force exerted by the ball on hands
• C. increase the rate of change of momentum
• D. decrease the rate of change of momentum

Answer 1

The correct option is B

reduce the force exerted by the ball on hands

Explanation for correct option:

B: reduce the force exerted by the ball on hands - The force $‘F’$ can also be defined as $F=\frac{∆p}{t}$ where $F,∆p$ and $t$ are force, impulse and time respectively. If time $\left(t\right)$ increases, then the force exerted by the football on the hand decreases. So, the goalkeeper pulls his hand backward.

Explanation for incorrect options:

A: exert larger force on the ball - As we know that if the time increases then force decreases. So, this is an incorrect option.

C: increase the rate of change of momentum - The rate of change of momentum of an object is proportional to the applied resultant force and is in the same direction as the applied resultant force. Also, we already explained that force is decreasing with increasing time. So, this is an incorrect option

D: decrease the rate of change of momentum - As we know that the goalkeeper increases the time interval to reduce the force. So, there is no relation to decreasing change of momentum. So, this is an incorrect option.

Hence, option B) is the final answer.