A detector is released from rest under gravity over a source of sound of frequency f0=103Hz. The frequency observed by the detector at time t is plotted in the graph. The speed of sound in air is (g=10m/sec2) (solve the problem by using apparent frequency relation, when the observer is moving with constant velocity)
300m/s
f=(Vs+V0Vs)f0⇒f=(Vs+gtVs)f0=f0+gf0Vst
Slope from graph = 10330=gf0Vs
⇒Vs=30103gf0=30103×10×103=300m/s