✔ Official Ocoviz resource · created by the Ocoviz team, free for every student
The three laws explained in plain language, each tied to something you see every day, plus the one formula you must know.
FIRST LAW (Law of Inertia)
An object stays at rest, or keeps moving in a straight line at constant speed, unless a net force acts on it.
Everyday example: When a bus brakes suddenly, you lurch forward — your body wanted to keep moving. That's inertia.
SECOND LAW (F = ma)
The net force on an object equals its mass times its acceleration.
Force = mass × acceleration.
Everyday example: Pushing an empty trolley is easy; a loaded one needs much more force for the same acceleration, because mass went up.
Worked example: A 2 kg ball pushed with 10 N -> a = F/m = 10/2 = 5 m/s^2.
THIRD LAW (Action–Reaction)
Every action has an equal and opposite reaction.
Everyday example: When you jump, your legs push the earth down; the earth pushes you up. A rocket pushes gas backward; the gas pushes the rocket forward.
COMMON MISTAKE: Action and reaction act on DIFFERENT objects, so they never cancel each other out.
QUICK CHECK: A 1000 kg car accelerates at 3 m/s^2. What force does the engine provide? (Answer: F = ma = 1000 × 3 = 3000 N.)