Physics

posted by .

A woman stands at the center of a platform. The woman and the platform rotate with an angular speed of 4.00 rad/s. Friction is negligible. Her arms are outstreched, and she is holding a dumbbell in each hand. In this position the total moment of inertia of the rotating system (platform, woman, and dumbbells) is 5.40kg.m2. By pulling in her arms, she reduces the moment of inertia to 4.40kg*m2. Find her new angular speed.

Apply the law of conservation of angular momentum.
I1*w1 = I2*w2
I2/I1 is the moment of inertia ratio. It equals w1/w2. Solve for w2.
w1 = 4.00 rad/s

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics - Conservation of Angular Momentum

    a man is standing on the center of a platform that is rotating without friction. his arms are outstretched holding a brick in each hand. the rotational inertia of the system consists of the man, bricks, and platform about the central …
  2. physics

    A child of mass 40 kg stands beside a circular platform of mass 90 kg and radius 1.6 m spinning at 2.8 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed; b) She then walks to the center …
  3. Physics

    A person of mass 55 kg stands at the center of a rotating merry-go-round platform of radius 3.4 m and moment of inertia 670 kg·m2. The platform rotates without friction with angular velocity 1.0 rad/s. The person walks radially to …
  4. Physics

    A child of mass 40 kg stands beside a circular platform of mass 115 kg and radius 1.6 m spinning at 3.8 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed; b) She then walks to the center …
  5. Physics

    A man stands on a platform that is rotating (without friction) with an angular speed of 1.21 rev/s; his arms are outstretched and he holds a brick in each hand The rotational inertia of the system consisting of the man, bricks, and …
  6. Physics

    A child of mass 40 kg stands beside a circular platform of mass 100 kg and radius 1.8 m spinning at 2.6 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed; rad/s b) She then walks to the …
  7. physics

    A woman with mass of 63 kg stands at the rim of a horizontal table having a moment of inertia of 520 kg m2 and a radius of 1.5 m. The turntable is initially at rest and is free to rotate about a frictionless, vertical axis through …
  8. Physics

    A woman with mass of 57 kg stands at the rim of a horizontal table having a moment of inertia of 570 kg m2 and a radius of 1.5 m.The turntable is initially at rest and is free to rotate about a frictionless, vertical axis through its …
  9. Physics

    A man stands on a freely rotating platform, as shown, holding an exercise dumbbell in each hand. With outstretched arms, his angular speed is 1.5 rad/s. After he has pulled his arms in, as shown, his angular speed is 5 rad/s. What …
  10. Physics

    A child of mass 30 kg stands beside a circular platform of mass 95 kg and radius 2.4 m spinning at 2.3 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed?

More Similar Questions