A 3 kg bowling ball is thrown onto a mattress. If it takes 0.3 seconds to stop the ball using a force of 24 N, what was the initial velocity of the bowling ball when it first touched the mattress?

2.4 m/s

Explanation:

Applying Newton's second law of motion,

F = m (v-u) / t ... Equation 1

Where F = force exerted on the ball, m = mass of the ball, v = final velocity of the ball, u = initial velocity of the ball, t = time required to stop the ball.

Note: Since the the ball come to stop, then v = 0 m/s.

F = - mu/t ... Equation 2

make u the subject of the equation

u = - Ft/m ... Equation 3

Given: m = 3 kg, t = 0.3 s, F = 24 N

Substitute into equation 3

u = - (24*0.3) / 3

u = - 2.4 m/s.

Note the negative sign tells that the initial velocity of the ball is in opposite direction to the force acting on the ball.