If û is a unit vector and T is a positive number with dimensions of stress, show that the stress tensor T = T00 represents uniaxial tension in the direction of 0. Determine the traction vector t and its normal component tn on a surface whose unit normal makes angle θ with a. what is the magnitude of the tangential component of the traction vector on the same surface?

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.