Combining Forces

Forces are at work all around us. Sometimes, they combine, like teammates, and sometimes they oppose each other, like a tug-of-war.

When two people push a box in the same direction, their forces add up. This total force is called the net force.

Imagine Person “A” pushes a box with 10 Newtons of force, and Person “B” adds 5 Newtons in the same direction. The net force on the box is 15 Newtons.

But what if two people pull on a rope in opposite directions?

If Person “A” pulls with 30 Newtons and Person “B” pulls with 20 Newtons, the rope moves toward Person “A” with 10 Newtons of net force.

This happens because objects move in the direction of the greater force.

Now, think of a book resting on a table. Gravity pulls it down while the table pushes it up with equal force. Since these forces cancel out, the book stays still.

Net force determines whether something moves or stays put. If forces are balanced, there is no change in motion. If they are unbalanced, a change in motion happens.