Newton’s Third Law of Motion

Explanation

This law states that for every reaction, there is an equal and opposite reaction. For example, if you lift a block of wood with a pulley, the force of the earth pulling down on the block will be equal to the force the rope exerts on the block. It is important to remember that every object in the universe attracts every other object. It is important to note however, that the equal forces do not affect acceleration, therefore the block moves. Forces always come in pairs.

Sample Problem

A student is playing tennis, as he hit the ball; due to the properties of Newton’s Third Law, the ball hit the racket and the racket hit the ball. Which force was greater?

Other Information:

The difference of mass and weight Mass and weight are not the same. Mass is how much material is inside an object. Force is the object’s weight. Weight is measured in Newtons.

External Links:

For more information, go to these links:

Glenbrook Physics Department
Wikipedia -- Newton's Laws