What is a force?

                                     What is a force?

A force is a push or a pull that gets something moving or changes the way it moves. Flicking a marble creates a force that sends the marble rolling across the table. Putting out your hand to stop it falling off the table’s edge creates a force that sends it spinning in another direction. If the marble rolls off the table, gravity pulls it to the ground – another force, of course!

WHAT’S IN A NAME?

Sir Isaac Newton’s three laws of motion, often called Newton’s Laws, explain how forces make objects move. Legend has it that and fell on Newton’s head while he was sitting under a tree, which led to his discoveries about motion and gravity.

Newton’s first law

An object will stay still or move along at the same speed and in the same direction unless a force acts upon it. This law is sometimes referred to as the law of inertia.

In action: If you brake too hard on your bike, you may go flying over the handlebars. The force exerted by the brakes has stopped the bike, but you keep moving forwards at the same speed.

Newton’s Second Law

The amount an object’s speed or direction changes depend on its mass and the size of the force acting upon it.

IN ACTION: If you exert a force on a marble by pushing it, it begins to move. But it takes more force to move a heavier object or to move something faster. So if you push a giant boulder it won’t move so far.

Newton’s third law

Whenever a force acts, an equal force acts in the opposite direction.

IN ACTION: When you jump, you push the ground with your feet,