Home
Class 11
PHYSICS
A diver having a moment of inertia of 6....

A diver having a moment of inertia of `6.0 kg-m^2` about an axis through its centre of mass rotates at an angular speed of 2 rad/s about this axis. If he folds his hands and feet to decrease the moment of inertia to 5.0 kg-m^2` what will be the new angular speed?

Text Solution

Verified by Experts

The correct Answer is:
A, B, D
`I=6kg-m^2,omega=2rad/s, I_2=5kgk-m^2`
since exterN/Al torque=0
Therefore `I_1omega_1=I_2omega_2`
rarr omega_2=(6xx2)/5`
`=12/5=2.4rad/s`
Promotional Banner

Topper's Solved these Questions

  • ROTATIONAL MECHANICS

    HC VERMA|Exercise Objective -2|15 Videos

  • REST AND MOTION : KINEMATICS

    HC VERMA|Exercise Exercises|51 Videos

  • SIMPLE HARMONIC MOTION

    HC VERMA|Exercise Exercises|58 Videos

Similar Questions

Explore conceptually related problems

Two small bals A and B, each of mass m, are joined rigidlyl by a light horizontal rol of lengh L. The rod is clasmped at the centre in such a way that it c an rotate freely about a verticl axis through its centre. The systemis rotated with an angualr speed omega about the axis. A particle P of masss m kept at rest sticks to the ball A as the ball collides with it. Find the new angular speed of the rod.

A constant couple of 500 Nm turns a wheel of moment of inertia 100 kg m^(2) about an axis through its centre. What will be the angular velocity gained by the body after 2 seconds ?

A wheel having moment of inertia 2 kg m^2 about its axis, rotates at 50 rpm about this axis. Find the torque that can stop the wheel in one minute.

A child stands at the centre of turn table with his two arms out stretched. 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 and thereby reduces his moment of inertia to 2/5 times the initial value? Assume that the turn table rotates without friction (ii) Show that the child's new kinetic energy of rotation is more than the initial kinetic energy of rotation. How do you account for this increase in kinetic energy?

A boy is seated in a revolving chair revolving at an angular speed of 120 revolutions per minute. Two heavy balls form part of the revolving system and the boy can pull the balls closer to himself or may push them apart. If by pulling the balls closer, the boy decreases the moment of inertia of the system from 6 kg-m^2 to 2 kg-m^2 what will be the new angular speed?

A wheel of moment of inertia 0.10 kg-m^2 is rotating about a shaft at an angular speed of 160 (rev)/(min) . A second wheel is set into rotation at 300 rev/minute and is coupled to the same shaft so that both the wheels finally rotate with as common angular speed of 200 rev/minute. Find the moment of inertia of the second wheel.

A dumb bell consists of two identicasl small balls offmss 1/2 kg each connected to the ends of a 50 cm long light rod. The dumb bell is rotating about a fixed axis through the centre of the rod and perpendicular to it t an angular speed of 10 rad/s. An impulsive force of average magnitude 5.0 N acts on one of the masses in the direction of its velocity for 0.10s. Find the new angular velocity of the system.

A wheel of moment of inertia 0.500 kg-m^2 and radius 20.0 cm is rotating about its axis at an angular speed of 20.0 rad/s. It picks up a stationary particle of mass 200 g at its edge. Find the new angular speed of the wheel.

A uniform rod of mass 300 g and length 50 cm rotates at a uniform angular speed of 2 rad/s about an axis perpendicular to the rod through an end. Calculate a. the angular momentum of the rod about the axis of rotation b. its kinetic energy.

A solid cylinder of mass 20kg rotates about it axis with anguler speed 100s^(-1) the radius of the cylinder is 0.25m, Calculate moment of intertia of the solid cylinder.

HC VERMA-ROTATIONAL MECHANICS-Exercises
  1. A dumb bell consists of two identicasl small balls offmss 1/2 kg each ...

    Text Solution

    |

  2. A wheel of moment of inertia 0.500 kg-m^2 and radius 20.0 cm is rotati...

    Text Solution

    |

  3. A diver having a moment of inertia of 6.0 kg-m^2 about an axis through...

    Text Solution

    |

  4. A boy is seated in a revolving chair revolving at an angular speed of ...

    Text Solution

    |

  5. A boy is standing on a platform which is free to rotate about its axis...

    Text Solution

    |

  6. A wheel of moment of inertia 0.10 kg-m^2 is rotating about a shaft at ...

    Text Solution

    |

  7. A kid of mass M stands at the edge of a platform of radius R which can...

    Text Solution

    |

  8. Suppose the platform of the previous problem is brought to rest with t...

    Text Solution

    |

  9. Suppose the platform with the kid in the previous problem is rotting i...

    Text Solution

    |

  10. A uniform rod of mass m and length l is struck at an end by a force F ...

    Text Solution

    |

  11. A uniform rod of length L lies on a smooth horizontal table. A particl...

    Text Solution

    |

  12. Suppose the particle of the previous problem has a mass m and a speed ...

    Text Solution

    |

  13. Two small bals A and B, each of mass m, are joined rigidlyl by a light...

    Text Solution

    |

  14. Two small balls A and B each of mass m, are joined rigidly to the end...

    Text Solution

    |

  15. Suppose the rod with the balls A and B of theprevious problem is clamp...

    Text Solution

    |

  16. Two blocks of masses 400 g and 200 g are connected through a light str...

    Text Solution

    |

  17. The pulley shown in figure has a radius of 20 cm and moment of inertia...

    Text Solution

    |

  18. A metre stick is is held verticaly with one end on a rough horizontal ...

    Text Solution

    |

  19. A metre stick weighing 240 g is pivoted at its upper end in such a way...

    Text Solution

    |

  20. A uniform rod pivoted at its upper end hangs vertically. It is displac...

    Text Solution

    |