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I have a doubt, kindly clarify. - Motion of System Of Particles and Rigid Body - NEET

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 \omega about their own symmetry axes. The amounts of work (W) required to bring them to rest, would satisfy the relation

  • Option 1)

    W_{B} > W_{A} > W_{C}

  • Option 2)

    W_{A} > W_{B} > W_{C}

  • Option 3)

    W_{C} > W_{B} > W_{A}

  • Option 4)

    W_{A} > W_{C} > W_{B}

 
Answers (1)
79 Views

As we have learned

Kinetic energy of rotation -

K=frac{1}{2}Iw^{2}

- wherein

I = moment of inertia about axis of rotation

w = angular velocity

 

 work energy theorem states that work done =change in kinetic energy

=\frac{1}{2}IW^{2}

I_{c}> I_{B}> I_{A}

\therefore K\cdot E_{c}> K\cdot E_{B}> K\cdot E_{A}

W_{c}> W_{B}> W_{A}

 

 

 

 

 

 


Option 1)

W_{B} > W_{A} > W_{C}

This is incorrect

Option 2)

W_{A} > W_{B} > W_{C}

This is incorrect

Option 3)

W_{C} > W_{B} > W_{A}

This is correct

Option 4)

W_{A} > W_{C} > W_{B}

This is incorrect

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