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 new angular velocity would be

A

`3 omega//5`

B

`4 omega//5`

C

`5 omega//4`

D

`5 omega//3`

Text Solution

Verified by Experts

Promotional Banner

Similar Questions

Explore conceptually related problems

Aballet dancer spins about a vertical axis at 120rpm with arms outstretched. With her arms folded the moment of inertia about the axis of rotation decreases by 40 %. What isnew rate of revolution ?

A ballet dancer spins about a vertical axis at 90 rpm with arms outstretched. With the arms folded, the moment of inertia about the same axis of rotation changes to 75 %. Calculate the new speed of rotation.

A ballet dancer spins about a vertical axis at 2.5pi rad s^-1 with his arms outstretched. With the arms folded, the M.I. about the same axis of rotation changes by 25%.Calculate the new speed of rotation in r.p.m.

A person stands on a uniformly rotating turn table with outstretched arms holding two identical weights. The moment of inertia of the system is 60 kgm^2 . When he brings the arms close to his body, the M.I. of inertia reduces to 58 kgm^2 . The angular speed of the system now becomes 3 rad s^-1 . Find the initial angular speed and the final K.E.

A man standing on a frictionless rotating platform rotates at 1 rps, his arms are outstretched and he holds a weight in his hands. In this position, the total moment of inertia of the system is 6 kg m^2 , he leaves the weights, the moment of inertia decreases to 2kg m^2 . The resulting angular speed of the platform is

A boy stands on a freely rotating platform with his arms extended. Hisrotation speed is 0.3 rev/s, when he draws in, his speed increases to 0.5 rev/s, then.the ratio of his moments of inertia in these two cases will be

A disc of moment of inertia I_1 , is rotating in horizontal plane about an axis passing through its centre and perpendicular to its plane with constant angular speed omega_1 . Another disc of moment of inertia I_2 having angular speed omega_2 The energy lost by the initial rotating disc is

Two discs of moments of inertia I_1 and I_2 about their respective axes normal to the disc and passing through the centre and rotating with angular speeds omega_1 and omega_2 are brought into contact face to face with their axes of rotation coinciding. Then the angular speed of the two disc system is

A person standing on a rotating platform with his hands lowered, outstretches his arms. The angular momentum of the person

A solid sphere of radius 20 cm and mass 25 kg rotates about an axis through its centre. Calculate its moment of inertia. If its angular velocity the torque applied changes from 2 rad s^-1 to 12 omega rad s^-1 in 5 sec, calculate the torque applied.