Pyschophysics is the study of the relationship between __ and

Blank liquids and gases exert a buoyant force on objects placed in them

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

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.