Question

What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren

Answer 1

Answer:

77.6 Hz

Explanation:

What frequency is received by a person watching an oncoming ambulance moving at 115 km/h and emitting a steady 753 Hz sound from its siren.

The given parameters are:

Observer speed = 115 km/h

Source frequency = 753 Hz

Speed of sound = 342 m/s

First convert km/h to m/s

Observer speed = (115 × 1000) / 3600

Observer speed = 31.94 m/s

The frequency received by the person will be:

F = fv / ( V - v )

Where

F = frequency received by the person

f = siren frequency

V = speed of sound

v = speed of the ambulance

Substitute all the parameters into the formula

F = (753 × 31.94) / ( 342 - 31.94 )

F = 24050.82 / 310.06

F = 77.568 Hz

Therefore, the frequency received by a person is approximately 77.6Hz