Question

A 1.2 kg ball falls in the -y direction at 25 m/s, strikes the floor, and rebounds at 10 m/s. What is the initial velocity before it struck the floor?

A) -20 m/s
B) -15 m/s
C) -25 m/s
D) -10 m/s

Answer 1

To calculate the initial velocity before the ball struck the floor, we can use the conservation of momentum. The momentum before the collision is equal to the momentum after the collision. Hence, the correct answer is D) -10 m/s.

Step-by-step explanation:

To calculate the initial velocity before the ball struck the floor, we can use the conservation of momentum. The momentum before the collision is equal to the momentum after the collision. Since the ball rebounds, its final velocity is in the opposite direction as its initial velocity. We can calculate the initial velocity by setting up the equation:

(mass of the ball)(initial velocity) = (mass of the ball)(final velocity)

(1.2 kg)(initial velocity) = (1.2 kg)(-10 m/s)

Solving for the initial velocity gives us:

initial velocity = -10 m/s

Therefore, the correct answer is D) -10 m/s.