A speeding motorcyclist sees traffic jam ahead him. He slows down to 36 km hour -1. He finds that traffic has eased and a car moving ahead of him at 18 km hour -1 is honking at a frequency of 1392 Hz. If the speed of sound is 343 ms-1, the frequency of the honk as heard by him will be

Here speed of Motorcyclist speed isvm=36 km hour -1=36×518 m s-1=10 m s-1Speed of car,vc=18 km hour -1=18×518 m s-1=5 m s-1Frequency of source, ν0= 1392 HzSpeed of sound, ν=343 m s-1The frequency of the honk heard by  the motorcyclist isv'=v0v+vmv+vc=1392343+10343+5=1392×353348=1412 Hz