Question

exert on you? Why doesn't this force make you rise up into the air?
when you stand still on the ground, how large a force does the ground​

Answer 1

Answer:

You probably know that the Earth pulls down on you. What you might not realize is that you are also pulling up on the Earth. For example, if the Earth is pulling down on you with a gravitational force of 500 N, you are also pulling up on the Earth with a gravitational force of 500 N. This remarkable fact is a consequence of Newton's third law.

Newton's third law: If 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.

This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself. We sometimes refer to this law loosely as action-reaction, where the force exerted is the action and the force experienced as a consequence is the reaction.

We can readily see Newton’s third law at work by taking a look at how people move about. Consider a swimmer pushing off from the side of a pool, as illustrated below.

Answer 2

Standing on the ground, normal force is exerted by the ground on the body. This force is balanced out by weight of the body.

Explanation:

• Any body that has mass will have some weight because of gravitational acceleration of the ground below it.
• Weight is given as mass times gravitational acceleration i.e. $mg$.
• Weight is the force that the body exerts on the ground exerts on the body due to gravity.
• Now, from Newton's third law of motion, "Any action of force will experience an opposite reaction force which will be equal in magnitude with the action force."
• So, here the gravitational force is the action force and then there is a reaction force that the ground will exert on the body. This reaction force is called Normal force.
• Normal force is exerted in upward direction on the body by the ground and is equal in magnitude to the gravitational force which is exerted by the body on the ground.
• So, weight of the body balances out the normal force. So, the body does not rise up in the air.