Which of the following options illustrate the positive effects of friction?
Frictional force
Gravitational force
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 our movement.
ii. It allows us to 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 paper. This causes the ink to fall out on paper.
iii. It is because of friction that a nail remains fixed to the wall.
There are many other positive effects of friction as well.