Newton's 3 laws of motion!

If an object is not moving
or moving at a constant speed,
the object will stay the way until
something moves or stops the
object.

seatbelt stops you from hitting the windshield if you hit the brakes quickly

A soccer ball will not move until a player kicks it

Also referred as Inertia.

Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).

You have to push a heavy ball harder to get it to move as fast as a small one

Push a large box & a small box with the same force, the small box will go faster

For every action, there is an equal and opposite reaction.

If air is let out of a balloon quickly, air pushes down & balloon goes up

A fireman turns on his hose & is knocked backwards