perpendicularly from each other, at v, = 8.50 m/s and v, = 12.0 m/s. Vehicle 1 sounds its horn at f = 450 Hz as it moves. The frequency f as heard by the driver of vehicle 2 changes over time. Take the speed of sound as v = 340 m/s. (a) Find the expression of f as a function of time. What is the value of at t = 1.5 s? (b) Now suppose a wind of speed u = 5.50 m/s blows along the direction of motion of vehicle 1. Redo part (a) above