Question

Which of the following statements is NOT true for friction force?

• A. Friction force is produced when two objects rub against each other
• B. A lighter object will experience a smaller frictional force
• C. Friction produces more wear and tear
• D. Friction is harmful

Answer 1

Answer: (D)

Friction is harmful

ADVANTAGES OF FRICTION
Friction plays a vital role in our daily life. Without friction we are handicap.
1. It is becomes difficult to walk on a slippery road due to low friction. When we move on ice, it becomes difficult to walk due to low friction of ice.
2. We can not fix nail in the wood or wall if there is no friction. It is friction which holds the nail.
3. A horse can not pull a cart unless friction furnishes him a secure Foothold.
DISADVANTAGES OF FRICTION
Despite the fact that the friction is very important in our daily life, it also has some disadvantages like:
1. The main disadvantage of friction is that it produces heat in various parts of machines. In this way some useful energy is wasted as heat energy.
2. Due to friction we have to exert more power in machines.
3. It opposes the motion.
4. Due to friction, noise is also produced in machines.
5. Due to friction, engines of automobiles consume more fuel which is a money loss.
So, Friction is useful for braking moving vehicles; for walking in smooth / slippery surfaces like snow and sand.
Answer (D) friction is harmful