Systems of Part...

A person standing on a rotating platform has his hands lowered. He suddenly outstretch his arms. The angular momentum

The radius of a rotating disc is suddenly reduced to half without any change in its mass. Then its angular velocity will be

What remains constant when the earth revolves around the sun?

A circular turn table has a block of ice placed at its centre. The system rotates with an angular speed ω about an axis passing through the centre of the table. If the ice melts on its own without any evaporation, the speed of rotation of the system

Before jumping in water from above a swimmer bends his body to

A boy stands over the centre of a horizontal platform which is rotating freely with a speed of 2 revolutions/sec about a vertical axis through the centre of the platform and straight up through the boy. He holds 2 kg masses in each of his hands close to his body. The combined moment of inertia of the system is 1 kg × m². The boy now stretches his arms so as to hold the masses of inertia of the system increases to 2 kg × m². The kinetic energy of the system in the latter case as compared with that in the previous case will

A homogeneous disc of mass 2 kg and radius 15 cm is rotating about its axis (which is fixed) with an angular velocity of 4 radian/s. The linear momentum of the disc is

If the earth is a point mass of 6 × 10²⁴ kg revolving around the sun at a distance of 1.5 × 10⁸ km and in time T = 3.14 × 10⁷s, then the angular momentum of the earth around the sun is

A boy comes running and sits on a rotating platform. What is conserved?

A man turns on a rotating table with an angular speed ω. He is holding two equal masses at arm\'s length. Without moving his arms, he just drops the two masses. How will his angular speed change?