A good soccer player can kick the ball up to 25 m/sec. A soccer ball has a mass of 800 grams (0.8 kg). What force must a goalie exert on the ball to bring it to rest in 0.1 sec?

200 N

Explanation:

Applying,

The force a golie must exert on the ball is,

F = ma Equation 1

Where m = mass of the ball, a = acceleration of the ball.

But,

a = Δv/t Equation 2

Where Δv = change in velocity, t = time.

Substitute equation 2 into equation 1

F = m(Δv/t) Equation 3

From the question,

Given: m = 0.8 g, t = 0.1 s, Δv = 25 m/s

Substitute these values into equation 3

F = 0.8×25/0.1

F = 200 N