Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the…

Three objects, A : (a solid sphere), B : (a thin circular disk) and C : (a circular ring), each have the same mass M and radius R . They all spin with the same angular speed ω about their own symmetric axes. The amounts of work (W) required to bring them to rest, would satisfy the relation
  1. WB>WA>WC
  2. WA>WB>WC
  3. WC>WB>WA
  4. WA>WC>WB

Solution

By work-energy theorem
W=loss in KE=12Iω2

IA=25MR2=0.4MR2
IB=12 MR2=0.5 MR2
IC=MR2
∴  WC>WB>WA

Asked in: NEET 2018

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