4 identical balls of radius R and mass M are lying in a gravity free space. The balls are in contact and their centres are forming vertices of a square of Side 2R in horizontal plane. One identical ball travelling vertically with speed V hits the four balls symmetrically. The collision is perfectly elastic. The centre of the four stationery balls are at (R,R,0),(R,-R,0),(-R,R,0) and (-R,-R,0).

A. find the speed of ball 1 after collision
B. calculate the speed of ball which was initially traveling with speed V just after collision
C. Find the unit vector in the direction of motion of ball 2 just after collision

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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