Question

Assertion : For two bodies, the sum of the mutual forces exerted between them is zero from Newtons third law.
Reason : The sum of work done by the two forces must always cancel.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

For two bodies, the sum of the mutual forces exerted between them is zero from Newtons third law.
i.e. $F_{12} + F_{21} = 0$
But the sum of the work done by the two forces need not always cancel.
i.e. $W_{12} + W_{21} \ne 0$
However, it may sometimes be true.