A roller coaster is designed such that riders experience ''weightlessness'' as they go round the top of a hill whose radius of curvature is 20 m. The speed of the car at the top of the hill is between

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

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)