MHT CET 2026 Physics question

PhysicsSystems of Particles and Rotational MotionMHT CET 2026

If the earth suddenly contracts to of its present size without change in its mass, the ratio kinetic energy of the earth after and before contraction will be (Earth is assumed to be a rotating sphere about itself)

Answer: (A)

Solution

No external torque acts, so angular momentum is conserved: . For a sphere ; with we get , so . Rotational kinetic energy

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Question ID VK-098571