A differential equation for the velocity of a falling mass m subjected to air resistance proportional to the square of the instantaneous velocity is m = m − 2 where > 0 is a constant of proportionality. The positive direction is downward. (a) Solve the equation subject to the initial condition (0) = 0. Hint: ∫ 2−2 = 1 tanh−1 ( ) + c (b)Use the solution in part (a) to determine the limiting, or terminal, velocity of the mass. That is, what happens to () as → [infinity]?