A ball is thrown vertically upwards from the ground.Work done by air resistance during its time of flight is …...............

1. Positive during ascent and negative during descent.
2. Positive during ascent and descent.
3. Negative during ascent and positive during descent.
4. Negative during ascent andd descent. Choose the correct one and explain.

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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