A football player, momentarily at rest on the field, catches a
football as he is tackled by a running player on the other team.
This is certainly a collision (inelastic!) and momentum must be
conserved. In the reference frame of the football field, there is
momentum before the collision but there seems to be none after
the collision. Is linear momentum really conserved? If so, ex￾plain how. If not, explain why.

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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