Unlike balanced forces, we say unbalanced forces when two forces acting on an object are not equal in size.

Unbalanced forces causes can cause:

• a still object to move
• a moving object to speed up or slow down
• a moving object to stop
• a moving object to change direction

Unbalanced forces make the wagon in the diagram speed up.

Notice that because there is a bigger force and a smaller force involved, the direction of the wagon will be determined by the bigger force. The wagon is moving as a result of unbalanced forces.