AIIMS2017Physics-Rotational Motion

AIIMS 2017 Physics Kinetic Energy of Rolling Objects Assertion Reason Question

Type: Assertion Reason-conceptual-Medium-Class 11

Assertion: The total kinetic energy of a rolling solid sphere is the sum of translational and rotational kinetic energies. Reason: For all solid bodies, total kinetic energy is always twice of translational kinetic energy.

A

If both assertion and reason are true and reason is correct explanation of assertion.

B

If both assertion and reason are true and reason is not correct explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Correct Answer

Option C

Detailed Explanation

The assertion is true because the total kinetic energy (KE) of a rolling solid sphere is indeed the sum of its translational kinetic energy (KE_trans = ½mv²) and rotational kinetic energy (KE_rot = ½Iω²), where I is the moment of inertia and ω is the angular velocity. However, the reason is false; for a solid sphere, the total kinetic energy is not always twice the translational kinetic energy; it is actually 2.5 times the translational kinetic energy due to the relationship between translational and rotational motion. Options A and B are incorrect because they assert the reason is a correct explanation of the assertion, which it is not, while option D is incorrect as the assertion is true.

Found an issue with this question?