Newton's laws

Definition

Newton's laws in plain English

Newton's three laws are the basic rulebook for how objects move when pushed or pulled. First law (inertia): things keep doing what they're doing — a resting object stays put and a moving one keeps gliding at the same speed and direction — unless a force changes that (this is why you lurch forward when a car brakes). Second law, F = ma, says the harder you push something and the lighter it is, the faster it speeds up — a shopping cart is easy to get moving, a loaded one isn't. Third law says every push comes with an equal push back the other way, which is exactly how a rocket works: it shoves gas down, and the gas shoves the rocket up.

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