An iron nail is driven into a block of ice by a single blow of a hammer. The hammerhead has a mass of 0.6 kg and an initial speed of 2.2 m/s. Nail and hammer are at rest after the blow. How much ice melts? Assume the temperature of both the ice and the nail is 0◦C before and after. The heat of fusion of ice is 80 cal/g. Answer in units of g.

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.