If the earth were to suddenly contract to half its present size, without any change in its mass, the duration of the new day will be
Two circular discs have masses in the ratio of 1:2 and radii in the ratio of 2:1. The ratio of their moments of inertia about the diameter is
The height of a solid cylinder is four times its radius. It is kept vertically at time t=0 on a belt which is moving in the horisontal direction with a velocity v=2.45 t x t . where v is in m/s and t is in second. If the cylinder doesnot slip, it will topple over at time t equal to
A mass m is moving with a constant velocity along a line parallel to the x-axis, away from the origin. Its angular momentum with respect to the origin
A uniform rod of length 1 metre is bent at its mid-point to make 90 degree angle. THe distance of the centre of mass from the centre of the rod is
Two particles A and B, initially at rest, move towards each other under a mutual force of attraction. At the instant when the speed of A is V and that of B is 2V, the speed of the centre of mass of the system is
A man, standing on a turn-table, is rotating at a centain angular frequency with his arms outstretch. He suddenly folds his arms. If his moment of intertia with folded arms is 75% of that with outstretched arms, his rotational kinetic energy will