A) An airplane flies with a velocity of 55.0 m/s [ 35 N of W] with respect to the air (this is known as air speed). If the velocity of the airplane according to an observer on the ground is 40.0 m/s [53 N of W], what was the wind velocity? B) If you were trying to cross a river with the shortest possible time, would you aim your boat slightly upstream, directly across the river, or slightly downstream? Explain