NEET2015Physics-Mechanics

NEET 2015 Physics Circular Motion MCQ Question

Type: MCQ-conceptual-Medium-Class 11

A mass m moves in a circle on a smooth horizontal plane with velocity v₀ at a radius R₀. The mass is attached to a string which passes through a smooth hole in the plane as shown. The tension in the string is increased gradually and finally m moves in a circle of radius R02\frac{R_0}{2}. The final value of the kinetic energy is

Question diagram
A

mv₀²

B

14\frac{1}{4} mv₀²

C

2 mv₀²

D

12\frac{1}{2} mv₀²

Correct Answer

Option B

Detailed Explanation

As the radius decreases, the angular momentum is conserved. Therefore, the kinetic energy remains the same as mv₀².

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