Question

Which of the following statements is incorrect?

• A. Friction opposes relative motion of objects.
• B. Friction produces heat.
• C. Friction can stop a moving object.
• D. Friction is never useful

Answer 1

The correct option is D

Friction is never useful

Friction is called as a necessary evil. It always opposes the relative motion between the objects. Friction can stop a moving object and it can also produce heat. You cannot write with a pen if there was no friction. Similarly, we cannot walk if there is no friction. Hence the statement friction is never useful is incorrect as there are many actions where friction plays an important role.