Question

a solid ball hits a stationary tennis ball in a perfectly elastic collision. if the mass of the plastic ball is three times that of the tennis ball, what statement is true?

Answer 1

In an elastic collision, both momentum and kinetic energy are conserved. If the mass of the plastic ball is three times that of the tennis ball, and the plastic ball hits the stationary tennis ball in a perfectly elastic collision, the plastic ball will rebound with the same speed as the tennis ball.

Step-by-step explanation:

In an elastic collision, both momentum and kinetic energy are conserved. If the mass of the plastic ball is three times that of the tennis ball, and the plastic ball hits the stationary tennis ball in a perfectly elastic collision, the statement that is true is:

The plastic ball will rebound with the same speed as the tennis ball.

To prove this, we can use the principles of conservation of momentum and kinetic energy.

1. Momentum conservation:

1. The total momentum before the collision is zero because the tennis ball is stationary. So, the momentum of the plastic ball before the collision is also zero.
2. After the collision, the total momentum of the two balls must still be zero, in accordance with the principle of momentum conservation.
3. Since the mass of the plastic ball is three times that of the tennis ball and the tennis ball is stationary, the plastic ball must rebound with the same speed as the tennis ball.

2. Kinetic energy conservation:

1. Before the collision, the total kinetic energy is zero because the tennis ball is stationary.
2. After the collision, the total kinetic energy of the two balls must still be zero, in accordance with the principle of kinetic energy conservation.

Therefore, the plastic ball will rebound with the same speed as the tennis ball in a perfectly elastic collision.

Answer 2

The plastic ball is heavier.
The total momentum is conserved.
The total energy is conserved.