Speed of a motor launch with respect to still water is 70m/s.Speed of stream is 3m/s.When the launch begins to travel upstream a float was dropped from it.The launch travel 4.2km upstream,turned about and caughtup with the float.How long is it before the launch reaches the floor.??

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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