Tug of War ‒ Composing Parallel Forces

In the model, there are three different situations that can occur when parallel forces are in the play.

**Forces in the opposite direction ‒ different sizes**

Truck exerts a greater force than a passenger car. When two forces act in the opposite direction, the resulting force is of the same direction as the larger force. The size of the resultant force equals the difference in sizes of the forces.

**Forces in the opposite direction ‒ same size**

Both cars use equally great force. When two equal forces act in the opposite direction, the resultant force (movement) is zero.

**Forces in the same direction**

All automobiles use equal forces. Two cars drive in the opposite direction than the first one. By applying more force in the same direction, the resulting force is of the same direction as the applied force. The size of the resultant force equals the sum of the sizes of the individual forces.