A block of mass 2kg is at rest on horizontal floor of a truck.

The coefficient of static friction between the block and floor is 0.7.

If the truck starts to move with a horizontal acceleration of 4 m/s^2, the frictional force on the block is?(if g=10m/s^2)

a)0N

b)4N

c)8N

d)14N

Plz 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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