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Question: Answered & Verified by Expert
A wheel is rotating freely with an angular speed ω on a shaft. The moment of inertia of the wheel is I and the moment of inertia of the shaft is negligible. Another wheel of moment of inertia 3I initially at rest is suddenly coupled to the same shaft. The resultant fractional loss in the kinetic energy of the system is:
PhysicsRotational MotionJEE MainJEE Main 2020 (05 Sep Shift 1)
Options:
  • A 56
  • B 14
  • C 0
  • D 34
Solution:
2624 Upvotes Verified Answer
The correct answer is: 34

From angular momentum conservation
Iω+0=IωC+3IωC
ωc=ω4

Loss of kinetic energy =12Iω2-12(I+3I)ω42

=12Iω2-12Iω24

=38Iω2

Fractional loss =34

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