Arefrigerator is to remove heat from the cooled space at a rate of 300 kj/min to maintain its temperature at -8 â°c. if the air surrounding the refrigerator is at 25 â°c, determine the minimum power input required for this refrigerator.

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.