A rectangular plate, whose streamwise dimension (or chord c) is 0.2 m and whose width (or span b) is 1.8 m, is mounted in a wind tunnel. The freestream velocity is 40 m/s. The density of the air is 1.2250 kg/m3, and the absolute viscosity is 1.7894 x 10-5 kg/m s. Plot (not sketch) the velocity profiles at x = 0.0 m, x = 0.05 m, x = 0.10 m, and x = 0.20 m. Calculate the chordwise distribution of the skin friction coefficient and the displacement thickness. What is the drag coefficient for the plate? Be sure to account for both sides of the plate.

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.