Pushing force making an angle theta to the horizontal is applied on a block of weight w placed ona a horizontal table. If the angle of friction is alpha, the magnitude of force required to move the body is equal to

a) (w cos(alpha))/(cos(theta+alpha))

b) (w sin(theta))/(cos(theta+alpha))

c) (w tan(theta))/(sin(theta+alpha))

d) (w sin(alpha))/(tan(theta+alpha))

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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