There are three balls A, B and C (rigid) of mass ''m'' each which are initially placed at the corners of an equilateral triangle of side length ''r'' in free space. At an instant, ball C is given a velocity tangential to the circumcircle of the triangle and the whole system is released free. For ball C to escape from the system, what should be the kinetic energy that should be given initially? Is the kinetic energy equal to the potential energy of the whole system (-3Gmm/r) or is it only equal to the potential energy between C and A; C and B (which is -2Gmm/r)??

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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