# Elastic Collision and Conservation of Momentum

## What happens when two carts collide elastically on a frictionless track?

Which of the following statements is true:

I. Carts 1 and 2 are both at rest

II. Cart 2 stops and cart 1 moves to the right with speed equal to the original speed of cart 2

III. Cart 1 remains at rest and cart 2 bounces back with speed equal to its original speed

IV. Cart 1 moves to the right with a speed slightly less than the original speed of cart 2 and cart 2 moves to the right with a very small speed

## Answer:

In an elastic collision between two masses on a frictionless track, the momentum and kinetic energy are conserved. Therefore, which statement from the options is true?

When two carts collide elastically on a frictionless track, they experience a transfer of momentum while conserving kinetic energy. This means that the sum of momentum before the collision is equal to the sum of momentum after the collision. Additionally, the total kinetic energy in the system remains constant.

In this scenario, option II is correct. Cart 2 would stop completely after colliding with Cart 1, and Cart 1 would then move to the right with a speed equal to the original speed of Cart 2. This outcome is a result of the conservation of momentum and energy in an elastic collision on a frictionless track.

Understanding the principles of momentum and kinetic energy conservation in elastic collisions can help in predicting the outcomes of such interactions in physics.