Newton's Laws of Motion ?

Sir Isaac Newton (1643–1727) formulated three fundamental laws that describe how objects move.

First Law — Law of Inertia:
An object at rest remains at rest, and an object in motion remains in motion with the same speed and in the same direction, unless acted upon by an unbalanced (net) external force.

Inertia is the tendency of an object to resist any change in its state of motion. Objects with greater mass have greater inertia.

Examples:
A book lying on a table stays there until someone pushes it.
A passenger lurches forward when a bus suddenly stops — the passenger's body wants to keep moving due to inertia.
Shaking a wet umbrella — the water drops fly off because they tend to continue in their original direction.

Second Law — Law of Acceleration:
The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Formula: Force = Mass × Acceleration (F = ma)

This means a larger force produces more acceleration, and a heavier object requires more force to produce the same acceleration.

Examples:
Pushing an empty shopping cart is easier than pushing a full one.
A cricket ball is hit harder, it travels faster.

Third Law — Law of Action and Reaction:
For every action (force), there is an equal and opposite reaction (force). Forces always occur in pairs — if object A exerts a force on object B, then object B exerts an equal and opposite force on object A.

Examples:
When you jump, you push the ground downward (action); the ground pushes you upward (reaction).
A rocket expels gas downward (action); the gas pushes the rocket upward (reaction).
Swimming: you push water backward (action); water pushes you forward (reaction).