5. Consider a model of a wing-body shape mounted in a wind tunnel. The flow conditions in the test section are standard sea-level properties with a velocity of 100m/s. The wing area and chord are 1.5m^2 and 0.45m, respectively. Using the wind tunnel force and moment-measuring balance, the moment about the center of gravity when the lift is zero is found to be -12.4N-m. When the model is pitched to another angle of attack, the lift and moment about the center of gravity are measured to be 3675N and 20.67N-m, respectively. Calculate the value of the moment coefficient about the aerodynamic center and the location of the aerodynamic center. Give your answer in terms of %MAC ahead or behind of CG. 6. Consider the model in Problem 5. If a mass of lead is added to the rear of the model such that the center of gravity is shifted rearward by a length equal to 20 percent of the chord, calculate the moment about the center of gravity when the lift is 4000N.