A driver of a car travelling with a speed 30m/s towards a hill souns a horn of frequency 600Hz.if the velocity of sound in air is 330m/s.calculate the frequency of reflected sound as heard by the driver?

Answer 1

The frequency of the reflected sound as heard by the driver can be calculated using the formula:

f' = (v +/- vD)/(v +/- vS) * f

where:
f = 600 Hz (frequency of the horn)
v = 330 m/s (velocity of sound in air)
vD = 30 m/s (velocity of the car towards the hill)
vS = -v (velocity of the reflected sound)
+/- means to use the plus sign if the listener is moving towards the source, and minus if moving away from the source

Substituting the values, we get:

f' = (330 + 30)/(330 - 330) * 600
f' = 660/0 * 600
f' = undefined

This means that the reflected sound cannot be heard by the driver, as it does not reach their ears.