Home
Class 12
PHYSICS
A dancer spins about himself with an ang...

A dancer spins about himself with an angular speed `omega`, with his arms extended. When he draws his hands in, his moment of inertia reduces by 40% . Then his angular velocity would be

A

`3omega//4`

B

`4omega//5`

C

`5omega//4`

D

`5omega//3`

Text Solution

Verified by Experts

The correct Answer is:
D
`w_(2)=(I omega xx 100)/(60I)=(5omega)/(3)`.
Promotional Banner

Topper's Solved these Questions

  • QUESTION PAPER - MH-CET 2018

    NIKITA PUBLICATION|Exercise MCQ|50 Videos

  • SEMICONDUCTORS

    NIKITA PUBLICATION|Exercise MCQS|350 Videos

Similar Questions

Explore conceptually related problems

A dancer is rotating on smooth horizontal floor with an angular momentum L The dancer folds her hands so that her moment of inertia decreases by 25%. The new angular momentum is

A child is standing with his two arms outstretched at the centre of a turntable that is rotating about its central axis with an angular speed omega_0 . Now, the child folds his hands back so that moment of inertia becomes 3 times the initial value. The new angular speed is.

A ballet dancer spins about a vertical axis at 120 rpm with arms out stretched. With her arms fold the moment of inertia about the axis of rotation decreases by 40% . What is new rate of revolution?

A child stands at the turn table center of a turnable with his two arms outstretched. The turnable is set rotating with an angular speed of 10 rad//s . If the child folds his hands back so that the moment of inertia reduces to 3//5 times the initial value, find the new angular speed. Why does the kinetic energy of child increase?

A person is standing on a rotating table with metal spheres in his hands. If he withdraws his hands to his chest, then the effect on his angular velocity will be.

An ice skater spins at 3pi" rad s"^(-1) with hers arms extended. If her moment of inertia with arms folded is 75% of that with arms extended, her angular velocity when she fold her arms is

A man stands at the centre of a circular table with his two hands outstretched. The table is set into rotation with an angular speed of 40 rev/min. What is the angular speed when the man folds his hands back and thereby reduces his moment of inertia 2/5 times the initial value? Assume that the table rotates without friction.

A child stands at the centre of a turn table with his two arms outstretched. The turn table is set rotating with an angular speed of 40 rpm. How much is the angular speed of the child, if he folds his hands back reducing the moment of inertia to (2//5) time the initial value ? Assume that the turn table rotates without friction. (b) Show that the child's new K.E. of rotation is more than the initial K.E. of rotation. How do you account for this increase in K.E. ?

A ballet dancer spins about a vertical axis at 60 rpm with his arms closed. Now he stretches his arms such that M.I. Increases by 50% . The new speed of revolution is

A diver having a moment of iertia of 6.0 kg-m^2 about an axis through its centre of mass rottes at an angular speed of 2 rad/s about this axis. If he folds his hands and feet to decrease the moment of inerti to 50.0 kg-m^2 what will be the new angular speed?

NIKITA PUBLICATION-ROTATIONAL MOTION -MULTIPLE CHOICE QUESTIONS
  1. If the radius of the earth decreases by 20% such that mass does not ch...

    Text Solution

    |

  2. A uniform disc of mass M and radius R is rotating in a horizontal plan...

    Text Solution

    |

  3. A dancer spins about himself with an angular speed omega, with his arm...

    Text Solution

    |

  4. A disc of mass 2 kg and radius 0.2 m is rotating about an axis passing...

    Text Solution

    |

  5. The diameter of a disc is 1m. It has a mass of 20kg. It is rotating ab...

    Text Solution

    |

  6. M.I. of a uniform horizontal solid cylinder of mass M about an axis pa...

    Text Solution

    |

  7. The moment of inertia of a circular ring about an axis passing through...

    Text Solution

    |

  8. A circular disc P of radius R is made from an iron plate of thickness ...

    Text Solution

    |

  9. Two solid sphere (A and B) are made of metals of different densities r...

    Text Solution

    |

  10. The M.I. of a circular ring of radius R and mass M about a tangent in ...

    Text Solution

    |

  11. The moment of inertia of a uniform circular ring, having a mass M and ...

    Text Solution

    |

  12. The mass of a thin circular plate is M and its radius is R. About an a...

    Text Solution

    |

  13. The M.I. of disc of mass M and radius 'R' about an axis passing throug...

    Text Solution

    |

  14. The moment of inertia of a disc of mass M and radius R about a tangent...

    Text Solution

    |

  15. The moment of inertia of a disc of mass M and radius R about a tangent...

    Text Solution

    |

  16. The M.I. of disc of mass M and radius 'R' about an axis passing throug...

    Text Solution

    |

  17. The moment of inertia of a straight thin rod of mass M and length l ab...

    Text Solution

    |

  18. The M.I. of thin uniform rod of mass 'M' and length 'l' about an axis ...

    Text Solution

    |

  19. The M.I. of a rectangular plane lamina of mass M, length 'l' and bread...

    Text Solution

    |

  20. If I(1),I(2) and I(3) are the moments of inertia about the natural axi...

    Text Solution

    |