A flat plate weighing 0.45 kN has a surface area of 0.1 m2 . It slides down an inclined plane at 30° to the horizontal, at a constant speed of 3 m/s. If the inclined plane is lubricated with an oil of viscosity 0.1 N.s/m2 , find the thickness of the oil film

A flat thin plate is dragged at a constant velocity of 4 m/s on the top of a 5 mm deep liquid layer of viscosity 20 centipoise. If the area of the plate is 1 m2 find the drag force. Assume variation of velocity in the liquid to be linear.