Question

Give some examples of Newton's third law of motion.

Answer 1

Example 1: How Birds Fly?
The wings of a bird force air downwards, this results in the air applying force of the same magnitude upwards. This pushes the bird upwards into the air. The same concept applies to planes and helicopters.

Example 2: Rocket Travel Made Possible
In the past space travel was considered impossible. This was because space was effectively vacuum. What can a rocket push against in vacuum? So what do present-day rockets do? When a rocket is started in space, hot gases are released in the opposite direction of the rocket. This results in an equal force in the forward direction on the rocket that pushes it ahead. This is a classic example of Newton’s Third Law.


Example 3: Hitting the Wall with your fist
Frustrated and hitting the wall with your fist? Well, Newton isn’t far away. Here there are two forces, your force and an equal and opposite force applied by the wall on the fist. Hence, harder you hit the wall the more force is exerted on your fist by the wall. This is why you get hurt more.

Example 4: How swimmers start off in a race?
In swimming races, while starting the swimmer uses his feet to push off the wall. The more force he applies on the wall, the faster will be his movement in water. The reason being the wall exerts the same force on the swimmer as he applies on the wall, but in the opposite direction.

Example 5: How sea animals move in water?

Let’s take an example of sea animals such as octopus. They suck in seawater and eject it through a siphon. As the octopus applies the force on the water, the water also exerts similar force but in the opposite direction. Sound familiar? Yes, it’s the Third Law of Motion at play again.

We hope these examples helped show you how the laws of Physics are at play all around us. They may sound basic, but they pack a lot.