A point mass m moving with velocity u towards the centre of the disc collides with a disc of mass m and radius r resting on a rough horizontal surface. Its collision is perfectly inelastic. Find angular velocity of system after pure rolling starts.

A) 2u/7r

B) 7u/2r

C) 5u/2r

D) 2u/5r

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

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