A girl rotates on a swivel chair. What happens to her angular speed when she stretches her arms?

A girl is standing on a turn table. What happens to the rotation speed if she stretches her hand?

A platform diver holds his hands and legs straight and makes loops in air before entering into water. What happens when he tries to land in the pool by stretching his arms and legs?

A solid cylinder of mass 20kg rotates about its axis with angular speed 100rad s^(-1) . The radius of the cylinder is 0.25m . What is the kinetic energy associated with the rotation of the cylinder? What is the magnitude of the angular momentum of the cylinder about its axis?

A 100 turn closely wound circular cell of radius 10 cm carries a current of 3.2A (a) what is the field at the centre of the coil? (b) What is the magnetic moment of this coil? The coil is placed in a vertical plane and is free to rotate about a horizontal axis which coincides with its diameter. A uniform magnetic field 2 T in the horizontal direction exists such that initially the axis of the coil is in the direction of the field. The coil rotates through an angle of 90^(o) under the influence of the magnetic field (c) What are the magnitudes of the torques on the coil in the initial and final position? (d) What is the angular speed acquired by the coil when it has rotated by 90^(o) ? The moment of inertia of the coil is 0.1 kg m^(2) .

Remya stands at the centre of a turn-table with her two arms outstretched. The table is set rotating with an angular speed of 40 revolutions per minute'. Write the expression for the rotational kinetic energy of the system and explain the terms

State the principle used by a ballet dancer to increase his/her angular speed.