Newton's Third Law

Detailed Explanation

Newton's Third Law states: "For every action, there is an equal and opposite reaction." This means that forces always come in pairs. When one object exerts a force on another, the second object exerts an equal but opposite force back on the first object.

Key aspects:

Forces are equal in magnitude but opposite in direction.
The forces act on different objects, not on the same object.
The law explains phenomena such as propulsion, walking, and collisions.

Example 1: When you jump off a small boat, you push the boat backward while you move forward.

Example 2: A rocket engine expels gas backward; as a reaction, the rocket moves forward.

Mathematical Insight

If object A exerts force F on object B, then object B exerts force -F on object A. Symbolically: F_AB = -F_BA

Applications

Some important applications include:

Airplane flight (thrust and air resistance)
Birds flying (wings push air down, air pushes wings up)
Recoil of guns (bullet forward, gun backward)

Quick Quiz

1) According to Newton's Third Law, what happens when you push on a wall?

2) When a rocket launches, the gas is pushed ___?

3) Forces in Newton's Third Law act on: