๐ Newton’s third law
Newton’s third law says: for every action, there is a reaction equal in magnitude and opposite in direction. In other words if there are two objects A and B, an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A.
What does this mean in our words and how can we understand it?
๐ Observation
Take a balloon and inflate it without tying it. Now release it and watch what happens. Repeat this several times. You can try to inflate the balloon differently each time – once less, next time more, and so on, and observe what happens.
Have you noticed that each time the balloon flies in the opposite direction to the direction of the air coming out of it, changing its direction of movement? And did you notice that a balloon that is more inflated flies faster?
Why was the ballon changing it direction? Because the end of the balloon is soft, flexible, and moves when the air comes out through it, which causes the balloon to change it direction.
Do you know the same principle described in Newton’s third law is used to launch space rockets?
If you haven’t seen a rocket launch, ask your parents to show you a video to watch what happens. The rocket detaches from the ground and takes off only after the engine has expelled enough gas with great force. Observe it and try to explain what happens, and why.
Newton’s third law applies also when you push a stroller for example. As you push the stroller, it pushes you with the same force, as incredible as it sounds.
Have you ever played throwing a ball against a wall? What was happening? Every time the ball hits the wall, it bounces off it and comes back to you. Why? Precisely because for every action, there is a reaction equal in magnitude and opposite in direction. By way of explanation, the wall repels the ball with the same force with which the ball hits the wall, but in the opposite direction to the direction of movement of the ball. Because of that the ball returns to you after colliding with the wall. This also happens when the ball bounces on the ground. Every time, after the ball hits the ground, it bounces back to you. The harder you hit the ball to the ground, the higher it bounces up after hitting the ground.
What does happen in space? Can Newton’s third law be applied there? Do bodies follow the same principle described in Newton’s third law? Try to find the answers by yourself.
Newton’s first law – see what it says.
Newton’s second law – check what it describes.