Discuss how you could measure Earth's diameter using nothing but a shadow-casting stick, a protractor, and a car's trip odometer if on a road trip between two cities that are approximately on the same line of constant longitude with a relatively straight shot of road connecting them.

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.