A gramophone disc rotates at 60 revolutions per minute. A coin of mass 13 g is placed at the disc at a distance of 8.0 cm from the centre. Calculate centrifugal force on the coin.

A horizontal disc rotating about a vertical axis makes 100 revolutions per minute. A small piece of wax of mass 10 g falls vertically on the disc and adheres to it at a distance of 9 cm from the axis. If the number of revolutions per minute is there by reduced to 90, calculate the moment of inertia of the disc.

A gramophone record is revolving with an angular speed .A coin is placed at a distance r from the centre of the record.RThe coefficient of static friction is u.the coin will revolve with the record if :

A man stands on a rotating platform, with his arms stretched horizontally holding a 5 kg weight in each hand. The angular speed of the platform is 30 revolutions per minute. The man then brings his arms close to his body with the distance of each weight from the axis changing from 90cm to 20cm. The moment of inertia of the man together with the platform may be taken to be constant and equal to 7.6 kg m^2 :- Is kinetic energy conserved in the process? If not, from where does the change come about?

A man stands on a rotating platform, with his arms stretched horizontally holding a 5 kg weight in each hand. The angular speed of the platform is 30 revolutions per minute. The man then brings his arms close to his body with the distance of each weight from the axis changing from 90cm to 20cm. The moment of inertia of the man together with the platform may be taken to be constant and equal to 7.6 kg m^2 :- What is his new angular speed? (Neglect friction.)

A ocnvex refracting surface of radius of curvature 20 cm separeates two media of refractive indices 4//3 and 1.60.An object is placed in the first medium (mu=4//3) at a distance of 200 cm from the refractign surface.Calculate the position of the image formed.

A wheel rotates making 20 revolutions per second. If the radius of the wheel is 35 cm., what linear distance does a point of its rim traverse in three minutes ?

A short bar magnet has a magnetic moment of 0.2 JT(-1) . Calculate the magnitude of the magnetic field produced by the magnet at a distance of 8 cm from the centre of the magnet on the equitorial line of the magnet.

Calculate the position of image, when an object is placed at a distance of 15 cm from a convex mirror having focal length 0.45 m.