Question

Suppose you are standing with your friend. Suddenly, you push your friend and he falls down. According to Newton's law third law, the friend has also pushed you with a force of equal magnitude. Why did you not fall down?

Answer 1

When you push your friend, your friend falls down but you don't fall down because:

1. The frictional forces acting between your feet and the ground prevents you from slipping as it balances with the reaction force. It balances the reaction force exerted by your friend on you.
2. If you have a higher mass, You may require lesser force to balance yourself. If you are fatter, you have less chance of falling down.