A disc of moment of inertia` 9.8/(pi^2)kgm^2` is rotating at 600 r.p.m. If the frequency of rotation changes from 600 r.p.m. to 300 r.p.m., then what is the work done?
A. 1470J
B. 1452J
C. 1567J
D. 1632J

A ceiling fan having moment of inertia 2kg -m^2 attains its maximum frequency of 60 rpm in 2 (pi) seconds. Calculate its power rating.

A body mass 100 g is revolving in a horizontal circle. If its frequency of rotation is 3.5 r.p.s. and radius of circular path is 0.5 m, the angular speed of the body is

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 coin just remains on a disc rotating at 120 r.p.m. when kept at the distance of 1.5 cm from the axis of rotation. Find the coefficient of friction between the coin and the disc.

A copper rod 1.5m long is rotated in a magnetic field of induction 6 xx 10^-5 (Wb)/m^2 .If it performs 1200 r.p.m.. find the e.m.f induced at its ends.

A wheel rotates with a constant angular velocity of 300 r.p.m. The angle through which the wheel rotates in one second is

An engine requires 5 s to go from a speed of 600 r.p.m to 1200 r.p.m. with constant acceleration. How many revolutions does it make in this period?