What is Newton’s third law of motion?
Newton’s third law of motion states that ‘every action has an equal and opposite reaction’. When two objects interact, there is a force on each object. The magnitude of force on the first object equals the magnitude of force on the second one.
For example, when you place an object on a table, the object exerts a force on the table (known as action force), and the table exerts a force on the object (known as reaction force). The magnitudes of the two forces are the same but the directions are opposite.
Forces acting on an object
Newton’s third law of motion – Example
When fired, a gun exerts a forward force on the bullet and the bullet exerts an equal and opposite reaction force on the gun that results in the recoil of the gun.
However, the gun does not recoil at the same acceleration as the bullet. Here, the two forces have the same magnitude of forces but different accelerations. This is because the mass of the gun is much more than that of the bullet. And according to Newton’s second law of motion, if the mass is more, the acceleration will be less. Hence, the acceleration of the gun is lesser than that of the bullet.