If the effects of the forces do not cancel each other, or if one force is stronger than the other, the forces are unbalanced forces. Unbalanced forces cause a change in motion, speed, and/or direction.

When two forces act in the same direction on an object, the net force is equal to the sum of the two forces. In the example below, the net force would be 900 Newtons (450 + 450 = 900), and the object would move to the right.

When two unequal forces act in opposite directions on an object, the net force is the difference of the two forces. In the example below, the net force would be 50 Newtons (500 - 450 = 50), and the object would move to the left because the force pulling to the left is greater.


Find the Net Force

Interactive exercise. Assistance may be required. In the problems below, find the net force, and then select what direction the object will move. The dot represents the object the forces are acting upon and the arrows show the direction the force is moving.