Sand is being dropped on a conveyer belt at the rate of M kg/s. The force necessary to keep the belt moving with a constant velocity of $$\upsilon $$ m/s will be :

A block B is pushed momentarily along a horizontaly surface with an initial velocity V. If  $$\mu $$  is the coefficient of sliding friction between B and the surface, block B will come to rest after a time

A block of mass m is placed on a smooth wedge of inclination $$\theta $$. The whole system is accelerated horizontally so that the block does not slip on the wedge. The force exerted by the wedge on the block will be (g is acceleration due to gravity)

The coefficient of static friction, $$\mu $$_s, between block A of mass 2 kg and the table as shown in the figure is 0.2. What would be the maximum mass value of block B so that the two blocks do not move? The string and the pulley are assumed to be smooth and massless. (g = 10 m/s²)