Question

If we apply oil on door hinges, the friction will

• A. increases
• B. decreases
• C. disappear altogether
• D. will remain unchanged

Answer 1

The correct option is B

decreases

Explanation for Correct Option:

Option (B):

1. Friction is the force that opposes the motion of a body.
2. It acts between the surface of contact of the body and on which it is moving.
3. It acts according to Newton's third law of motion.
4. In order to perform a motion, the force applied to start the motion must be greater than the frictional force.
5. Hence, upon applying oil on door hinges, the friction decreases.

Explanation for Incorrect Option:

Option (A):

1. Oil always reduces friction on the surface on which it is applied.
2. Hence, upon applying oil on door hinges, the friction does not increase.

Option (C):

1. Under practical circumstances, a completely frictionless body is not possible to obtain.
2. Hence, upon applying oil to door hinges, the friction does not disappear altogether.

Option (D):

1. Oil always reduces friction on the surface on which it is applied.
2. Hence, upon applying oil on door hinges, the friction will change.