Question

Which of the following options illustrate the positive effects of friction?

• A. Magnetic force
• B. Frictional force
• C. Gravitational force
• D. Air pressure

Answer 1

The correct option is D

Air pressure

Friction is often called a necessary evil as it has both positive and negative effects. Some of the positive effects of friction are:

i. It makes us walk. It provides an opposing force which helps us in moving.
ii. It makes us write on a sheet of paper. While writing, the ball inside the pen rolls because of the frictional force acting between the ball and the surface of the paper. This causes the ink to fall out on paper. Otherwise, the ball will slide if the frictional force is absent.
iii. It is because of friction that a nail remains fixed to the wall.

There are many other positive effects of friction as well.