Question

Is it true that two bodies exert force on each other only when they are in contact with each other?

Answer 1

Force is described as the effort done to bring about a change in the object. This change can be in the form of change of shape, size, orientation, velocity or configuration of the object. These forces classified as,
Contact forces
Non-Contact forces
Contact forces are those forces where the interacting bodies make a contact by the virtue of which a change is imparted onto the bodies.
Non-Contact forces are those forces where the interacting bodies are not in direct contact but still in the presence of each other, demonstrating a change.

Complete step by step solution:
We define force to be a phenomenon in which some effort is done to impart a change in some object. Depending upon the relative positions of the interacting bodies, forces can be classified into two types.
Contact forces –Where the interacting bodies are in physical contact. This force acts on the point of direct contact of the bodies.
Non-Contact forces - where the interacting bodies are not in any physical contact
Examples of contact forces are frictional force, normal reaction, tension in a string, spring force.
Examples of non-contact forces are gravitational force, electrostatic force, magnetic force.
Consider some real-life examples:
An apple falls down from a tree
A magnet attracts iron pins
When you rub a comb on dry hair, it attracts a bit of paper.
In all the above examples there is no direct contact of the objects but still a push or pull has been experienced. So, we can say that for a force to act, it is not necessary that the bodies should be in direct contact.
Hence, it is false if we say that two bodies exert force on each other only when they are in contact with each other

Note:
In non-contact forces, the push or pull effect is due to the presence of a particular field around the object under whose influence it undergoes any change. This field is different in different non-contact forces. It is the gravitational field that makes an object experience the gravitational force while an electric field that makes an object experience electrostatic force.