force

Force is a push or pull that can change an object’s motion, shape, or direction.

• A force can make a still object start moving, such as kicking a football.
• It can change the motion of something already moving: brakes slow a bicycle, while a bat sends a cricket ball in a new direction.
• Forces can also change shape. Squeezing a sponge, stretching a rubber band, or compressing a spring all involve forces.
• A force acts on an object through a contact, such as your hand pushing a box, or from a distance, such as Earth’s gravity pulling objects downward.
• Forces have both size and direction. Pushing a shopping trolley harder makes a bigger effect, and pushing it from the side can turn it.

Forces are happening all around us: when we walk, ride, throw, open a door, or even hold a book still against gravity.