When two objects interact, the forces they exert on each other are equal and opposite. (For every action there is an equal and opposite reaction.)All forces arise in pairs. The Newton 3 pairs are always:of the same typeacting on different objectsequal and opposite
For example when a man sits on a chair, there are two contact forces that are equal and opposite to each other.The contact force of the chair on the man and the contact force of the man on the chair.The electrons surrounding the atoms of the chair repel the electrons surrounding the atoms of the man. Both forces are the same type of force and are both contact forces which are electrostatic forces of repulsion.
When the man sits on the chair there are also two gravitational forces that are equal and opposite: one acts on the man and the other acts on the Earth. There would be a gravitational force on the man whether he was sitting on the chair or not.There is the gravitational force of the Earth pulling the man downwards and the gravitational force of the man pulling the Earth upwards.These forces are equal and opposite and both gravitational and both acting on different objects.
For example when a man sits on a chair, there are two contact forces that are equal and opposite to each other.The contact force of the chair on the man and the contact force of the man on the chair.The electrons surrounding the atoms of the chair repel the electrons surrounding the atoms of the man. Both forces are the same type of force and are both contact forces which are electrostatic forces of repulsion.
When the man sits on the chair there are also two gravitational forces that are equal and opposite: one acts on the man and the other acts on the Earth. There would be a gravitational force on the man whether he was sitting on the chair or not.There is the gravitational force of the Earth pulling the man downwards and the gravitational force of the man pulling the Earth upwards.These forces are equal and opposite and both gravitational and both acting on different objects.