Newton's 3rd law states that for every action, there is an equal and opposite reaction. This means that when an object exerts a force on another object, the second object will exert an equal and opposite force back on the first object.
When a gun is fired, the gunpowder inside the bullet explodes, creating a force that pushes the bullet out of the barrel. This is the action. The bullet then exerts an equal and opposite force on the gun, causing it to recoil or kickback. This is the reaction.
The bullet moves forward because the force of the explosion is greater than the force of the gun's recoil. This is due to the difference in mass between the bullet and the gun. The bullet has less mass, so it accelerates faster and moves forward.
No, Newton's 3rd law applies to all interactions between objects. For example, when you walk, your feet push against the ground (action), and the ground pushes back with an equal and opposite force, propelling you forward (reaction).
No, Newton's 3rd law is a fundamental principle of physics and has been proven to be true in countless experiments. It is a fundamental concept that governs the motion of all objects in the universe.