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 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 90 rpm with arms outstretched. With her arms folded, the M.I. about the axis of rotation decreases to 75%.Calculate the new rate of revolutions

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 flywheel of mass 4 kg has radius of gyration 0.4 m. Calculate the kinetic energy of rotation when it makes 5 r.p.s

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 uniform ring of mass M of outside radius r_(2) is fitted tightly with a shaft of radius r_(1) . If the shaft is rotated with a constant angular acceleration. About it's axis, the moment of the elastic force in the ring about the axes of rotation is

A solid sphere has a radius R . If the radius of gyration of this sphere about its diameter is sqrt(2//5) R , show that the radius of gyration about the tangential axis of rotation is sqrt(7//5) R

Two wheels of moment of inertia 4 kgm^2 rotate side by side of the rate of 120 r.p.m. and 240 r.p.m. respectively in the opposite direction. If now both the wheels are coupled by means of weightless shaft so that both the wheels now rotate with a common angular speed, find the new speed of rotation.

A horizontal disc is freely rotating about a vertcal axis passing through its centre at the rate of 125 r.p.m. A blob of wax of mass 50 gm falls on it and sticks to it at a distance of 10 cm from the axis. If the reslting frequency of rotation is 75 r.p.m, calculate the moment of inertia of the disc.

If the diameter of flywheel is increased by 1%, then increase in its M.I. about an axis passing through centre and perpendicular to the plane will be