Question

Friction is not required in which of the following cases?

• A. Man running on the ground.
• B. Friction between parts of a machine.
• C. Writing with a pen.
• D. Monkey climbing a tree.

Answer 1

The correct option is B Friction between parts of a machine.

A) If there is no friction between man and ground then man will slip/ fall.

B) If there is no friction between parts of machine then there is no loss of energy and work efficiency increases.

C) If friction is not present between pen and copy then we cannot write properly.

D) Friction is required for a monkey to climb on tree otherwise it will slip down.

Hence Option B