Two metal balls with the same mass hang so that they are touching each other. The ball on the left is pulled to the side and released. What will happen when it swings back and hits the ball on the right?

Question

The ball on the left will stop, and the ball on the right will remain still.
The ball on the left will stop, and the ball on the right will remain still.

The ball on the right will swing to the right
The ball on the right will swing to the right

Both balls will swing to the right.
Both balls will swing to the right.

Both balls will swing to the left.

Answer 1

When the ball on the left is pulled to the side and released, it swings down and gains kinetic energy due to its gravitational potential energy. Upon swinging back and colliding with the stationary ball on the right, the behavior of both balls can be predicted based on the principles of conservation of momentum and energy.

Since both balls have the same mass and are perfectly elastic, here's what happens upon collision:

• The ball on the left will transfer its momentum and energy to the ball on the right.
• After the collision, the ball on the left will come to a stop, and the ball on the right will swing off to the right with the same speed that the ball on the left had before the collision.

Therefore, the correct outcome would be:

The ball on the left will stop, and the ball on the right will swing to the right.