Q15.16Multiple correct
A train, standing in a station yard, blows a whistle of frequency 400 Hz in still air. The wind starts blowing in the direction from the yard to the station with a speed of 10m/s. Given that the speed of sound in still air is 340m/s,
- (a)the frequency of sound as heard by an observer standing on the platform is 400Hz.
- (b)the speed of sound for the observer standing on the platform is 350m/s.
- (c)the frequency of sound as heard by the observer standing on the platform will increase.
- (d)the frequency of sound as heard by the observer standing on the platform will decrease.