Question

Assertion :A body may gain kinetic energy and potential energy simultaneously. Reason: Conservation of mechanical energy may not be valid every time.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Yes, the Assertion is correct that a body may gain kinetic energy and potential energy simultaneously.

For example, a body is taken upward by continuously applying a force in the upward direction. Due to the upward force, the velocity (hence kinetic energy) of the body increases and as the body goes higher, its potential energy also increases.

But this system is not an isolated system as an external force is applied to it. Mechanical energy is conserved only when the forces acting on the system are conservative. Thus the reason is also correct and explains the assertion very well.

If conservative forces act on the system, then the mechanical energy of the system is conserved. Then the body does not gain kinetic energy and potential energy simultaneously.

Hence option A is correct.