question_answer

What are contact and non-con tact forces? Explain briefly, with suitable examples.                                         

Answer:

Forces can be of two types:

(i) Contact forces.

(ii) Non-contact forces.

(i) Contact forces: The forces that come into play when two objects come in contact with each other.

(a) Muscular force: The force which is exerted due to action of muscles is known as the muscular force, e.g., running, bending, walking etc.

(b) Frictional force: The force responsible for changing the state of motion of an object. Equal and opposite forces are being exerted on an object when its surface comes in contact with other surface, e.g., a car or scooter comes to rest.

(ii) Non-contact forces: The forces that can be exerted from a distance without establishing a contact are called the non-contact forces.

(a) Magnetic force: Force exerted by a magnet on another magnet or magnetic substances like iron is called magnetic force, e.g., Car sticking to an electromagnet.

(b) Electrostatic force: Force exerted by a charged body on another charged body or uncharged body is called electrostatic force, e.g., If we rub a comb with hair and bring it near some small bits of paper, it attracts the bits of paper towards itself. This is electrostatic force.

(c) Force of gravity: The earth pulls every object towards its centre. The force exerted by the earth is called the force of gravity.