A moving ball hits a stationary ball. The moving ball stops, and the stationary ball starts moving. In terms of force, what's happening during this event?

The stationary ball exerts a force on the moving ball.

The moving ball exerts a force on the stationary ball.

Explanation:

When two objects collide, each object exerts a force on the other. Unlike energy, force can't be transferred between objects. Force has strength and direction, but it isn't a property of an object.

When the moving ball collides with stationary ball then the moving ball experiences a force which opposes its motion offered by stationary ball.

Simultaneously stationary ball is experiencing a force which causes the stationary ball to move.

There is simultaneous exchange of forces which changes the present inertia of balls.