A golf ball is rolling in the grass. What must happen to stop the ball from continuing to roll?

An unbalanced net force must be applied.

A balanced net force must be applied.

The net force must be zero.

The net force must be greater than the applied force.

The net force must be zero

This is in accordance to Newton's first law, which states that any object in motion will remain in motion and any object at rest will remain at rest unless acted upon by an unbalanced force. An unbalanced force is one where the net force is not zero. If no unbalanced force is applied to a moving object, it will keep moving forever. The reason that we do not observe this in our daily lives is due to friction acting as the unbalanced force.