A cubical box of side 'a' sitting on a table top is pushed horizontally with a gradually increasing force until the box moves. If the force is applied at a height from the table top which is greater than the critical height H, the box topples first. If it applied at a height lesser than the critical height then the box starts sliding first. Then the coefficient of friction between the box and table top is

a) 2/H b) 2H/a c) a/H d) H/a

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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