A DIY person is driving home from the local home improvement store with a 4-ft by 8-ft sheet of plywood attached to the roof of the car. If the car’s speed is 35 mph and assuming the air flow is parallel to the plywood a) estimate the boundary layer thickness at the endo of the board, b) estimate the drag on the plywood is the boundary layer remains laminar, and c) estimate the drag is the boundary layer is turbulent (assume the wood is smooth).

Air at a pressure of 1atm and a temperature of 40 c is in parallel flow over the top surface of a flat plate that is heated to a uniform temperature of 120 c. the plate has a length of 0.40m (in the flow direction) and a width of 0.15m. the reynolds number based on the plate length is 50, 000. what is the rate of heat transfer from the plate to the air? if the free stream velocity of the air is doubled and the pressure is increased to 10 atm what is the rate of heat transfer?