Theenergy stored in a coil of self-inductance, L, and traversed by current I, is E1. A second coil is made with the same length of wire, but its radius is twice the radius of the first coil and it is twice as long as the first coil. If the second coil also has twice the current of the first coil, how does the energy stored in the first coil, E1, compare to the energy stored in the second coil, E2

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.