two blocks of masses m₁ and m₂are placed in contact with each other on a horizontal platform . the coefficent of friction between m₁ and the platform is 2µ and between block m₂ and platform is µ . the platform moves with an acceleration a . the normal reaction between the blocks is:

a. zero in all case

b. zero only if m₁ = m₂

c. non zero only if a > 2µg

d. non zero if a > µg

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.

11

21

31

41