Newton's Third Law of Motion

"For every action, there is always an equal but opposite reaction."

The action and reaction acts on different object but at the same time. The reaction exert an equal amount of force with the action but in opposite direction. The third law describes that everytime two objects interact with each other, they exert force to each other - action and reaction forces. Because of this, the third law is also called Law of Interaction.

Situation 1.

What makes a bird fly? As the bird flaps its wings, the wings exerted an action force downward into the air and at the same time the air reacted by pushing the bird's wings in upward direction. This interaction between the bird's wings and the air causes the flying motion of the bird.



Situation 2.

Pon wanted to know how to swim. What must he do to be able to swim? Swimming is also caused by the interaction of action and reaction forces. The arms pushes the water backward and at the same time the water pushes the arms forward causing a forward motion.

Situation 3.

Walking is also explained by the third law. As the feet step on the ground, it exerted a downward action force to the ground and in return, the ground pushes the feet upward causing a forward motion.

Situation 4.

The flying of the rocket results from the interaction of two forces. Fuels are burned in the engine of a rocket producing hot gases. These hot gases comes out at the bottom of the rocket's tube in downward direction and at the same time causing the rocket to fly upward.