Question

A speeding motorcyclist sees trafic jam ahead of him. He slows down to 36 km/hour. He finds that traffic has eased and a car moving ahead of him at 18 km/hour is honking at a frequency of 1392 Hz. If the speeds of sound is 343 m/s, the frequency of the honk as heard by him will be :(a) 1332 Hz(b) 1372 Hz(c) 1412 Hz(d) 1464 Hz

Answer 1

also tell me the answer

Answer 2

Answer:

C) 1412

Explanation:

Vl = 36km/hr ( Given)

Vs = 18km/hr ( Given)

Vl = 18×5/18 = 5

Vs = 36×5/18 = 10

Thus, Vl = 36km/hr = 10m/s

Vs = 18km/hr = 5m/s

v = 343 m/s ( Given)

v = [ v+vl/v+vs]

  = 1392[343+10/343+5]

  = 1412 Hz

Thus, the frequency of the honk heard will be = 1412Hz