Question

List two ways in which friction can be increased and two ways in which it can be decreased to our advantage.

Answer 1

Friction force:

1. The frictional force is a contact force that acts between two surfaces in contact.
2. On a microscopic level, even a smooth-looking surface has irregularities.
3. When an object is placed over another object these irregularities get interlocked and oppose the motion.

Ways to reduce friction:

1. Applying lubricant: Lubricant forms a thin layer between surfaces which smoothens the irregularities present on the surface.
2. For example, oil is applied on door hinges to reduce friction.
3. Using ball bearings and wheels: As rolling friction is less than sliding and static friction therefore wheels are used to move heavy objects.

Ways to increase friction:

1. Friction can be increased by making the surface more irregular or rough.
2. Grooves and treads are made on shoes and tires respectively so that friction can be increased.
3. Applying coarse substances: Gymnasts applies coarse substance such as chalk powder on their hand to increase friction.