please read carefully this is different from similar posted solutions on chegg.

(Hint: Solving problem 2 will help you with problem 3.) A layer of molten slag with a density of 2700kg/m3 and viscosity of 0.3Pas is being transferred from one furnace to another by flow down a plane between the two furnaces. The plane is inclined at an angle of 80 to the vertical and is 5m wide and 5m long. The mass flow rate of the slag is 7.5kg/s. Assume laminar flow. Please calculate: a) The thickness of the layer. b) The average linear velocity of the slag. c) How long on average the fluid spends on the plane (the residence time)