Home
Class 12
PHYSICS
A man, sitting firmly over a rotating st...

A man, sitting firmly over a rotating stool has his arms streched. If he folds his arms, the work done by the man is.

A

zero

B

positive

C

negative

D

may be positive or negative.

Text Solution

Verified by Experts

The correct Answer is:
B
Promotional Banner

Topper's Solved these Questions

  • 10 ROTATIONAL

    MOTION|Exercise Exercise - 2 (Level -I)|51 Videos

  • 10 ROTATIONAL

    MOTION|Exercise Exercise - 2 (Level - II)|25 Videos

  • 10 ROTATIONAL

    MOTION|Exercise Example 31|1 Videos

  • ALTERNATING CURRENT

    MOTION|Exercise EXERCISE - 4 (LEVEL - II)|14 Videos

Similar Questions

Explore conceptually related problems

A person sitting firmly over a rotating stool has his arms stretched. If he folds his arms, his angular momentum about the axis of rotation

A man is sitting on a rotating stool with his arms outstretched. If suddenly he folds his arms the angular velocity of the man would

A gymnast standing on a rotating stool with his arms outstretched, suddenly lowers his arms

If a gymnast sitting on a rotating disc with his arms out stretched suddenly lower his arms, then

If a person sitting on a rotating stool with his hands outstretched, suddenly lowers his hands, then his

A person is standing on a rotating platform, with his arms at his sides. If he stretches his arms, then which of the following statements is correct?

A preson is standing on the centre of a rotating table with his arms outstretched. The table is rotating freely with an angular his hands towards his chest. The moment of inertia reduces to (3)/(5) time the original moment of inertia. Calculate angular speed of the man when he withdraws his hands.

A man stands on a rotating platform with his arms stretched holding a 5 kg weight in each hand. The angular speed of the platform is 1.2 rev s^-1 . The moment of inertia of the man together with the platform may be taken to be constant and equal to 6 kg m^2 . If the man brings his arms close to his chest with the distance n each weight from the axis changing from 100 cm to 20 cm . The new angular speed of the platform is.

A man stands on a rotating platform, with his arms stretched horizontal holding a 5 kg weight in each hand. The angular speed of the platform is 30 revolutions per minute. The man then brings his arms close to his body with the distance of each weight from the axis changing from 90 cm to 20 cm . moment of inertia of the man together with the platform may be taken to be constant and equal t 7.6 kg m^(2) . (a) What is the his new angular speed ? (Neglect friction.) (b) Is kinetic energy conserved in the process ? If not, from where does the change come about ?

MOTION-10 ROTATIONAL-Exercise - 1
  1. A particle moves with a constant velocity parallel to the X-axis. Its ...

    Text Solution

    |

  2. A person sitting firmly over a rotating stool has his arms stretched. ...

    Text Solution

    |

  3. A man, sitting firmly over a rotating stool has his arms streched. If ...

    Text Solution

    |

  4. A particle of mass 2 kg located at the position (vec(i) + vec(j)) m ...

    Text Solution

    |

  5. The angular momentum of a flywheel having a moment of inertia of 0.4 ...

    Text Solution

    |

  6. The rotational kinetic energy of a rigid body of moment of inertia 5 ...

    Text Solution

    |

  7. The angular velocity of a body changes from one revolution per 9 sec...

    Text Solution

    |

  8. A dog of mass m is walking on a pivoted disc of radius R and mass M in...

    Text Solution

    |

  9. A particle starts from the point (0m, 8m) and moves with uniform veloc...

    Text Solution

    |

  10. A uniform rod kept vertically on the ground falls from rest. Its foot ...

    Text Solution

    |

  11. A thin uniform rigid rod of length L is hinged at one end so that it c...

    Text Solution

    |

  12. A thin uniform heavy rod of length l hangs from a horizontal axis pass...

    Text Solution

    |

  13. A uniform rod of mass M & length L is hinged about its one end as sh...

    Text Solution

    |

  14. Two identical rod are joined as shown. The system is pivoted at point ...

    Text Solution

    |

  15. A ball of mass m moving with velocity v, collide with the wall elastic...

    Text Solution

    |

  16. A uniform rod of mass M has an impulse applied at right angles to one ...

    Text Solution

    |

  17. A particle P strikes the rod R perpendicularly as shown. The rod is su...

    Text Solution

    |

  18. A particle P strikes the rod R perpendicularly as shown. The rod is su...

    Text Solution

    |

  19. A particle P strikes the rod R perpendicularly as shown. The rod is su...

    Text Solution

    |

  20. Two separate cylinders of masses m(=1 kg ) & 4m radii R(=10cm) and 2R ...

    Text Solution

    |