A large wooden plate of area 10 m2 floating on the surface of a river is made to move horizontally with a speed of 2 m/s by applying a tangential force. River is 1 m deep and the water in contact with the bed is stationary. Then choose correct statement.(coefficient of viscosity of water = 10-3 N-s/m2)
(a) velocity gradient is 2 s-1
(b) velocity gradient is 1 s-1
(c) force required to keep the plate moving with constant speed is 0.02 N
(d) force required to keep the moving with constant speed is 0.01 N