Ethel is sitting on a park bench feeding the pigeons when a child's ball rolls toward her across the grass. Ethel returns the ball to the child by hitting it with her 2.0-kg pocketbook with a speed of 20 m/s. If the impact lasts for 0.4 s, with what force does Ethel hit the ball?

100N

Explanation:

Given parameters:

Mass of pocketbook = 2kg

Velocity = 20m/s

time of impact = 0.4s

Unknown:

Force Ethel hits the ball = ?

Solution:

The impact can be best pictured as the impulse of the ball on the pocket book. Impulse is the time taken for a force to act.

         Impulse  = Force x time

Impulse is the same as momentum;

            Momentum = mass x velocity

       therefore equating impulse and momentum;

        Force x time = mass x velocity

       Force =  = 100N

hey , the answer is c