Two engines pass each other moving in opposite directions with uniform speed of 30 m/s. one of them is blowing a whistle of frequency 540 Hz. Calculate the frequency heard by driver of second engine before they pass each other. speed of sound is 330 m/sec:

Step-by-step solution

From Doppler's effect of sound, apparent frequency is given by, f ′ = v + v 0 v - v s f , where v ,   v o ,   v s & f represents velocity of sound, velocity of observer, velocity of source and frequency of source repectively. = 330 + 30 330 - 30 × 540 = 360 300 × 540 = 648   H z