You blow a whistle of frequency 942 Hz, as you move towards a wall.

The frequency of beats you hear from the whistle and the reflected sound is 7 beats/s.

In m/s and to two significant figures, how fast are you moving towards the wall?

1 answer

942+7= 949

949 = f (340+v/340)

f= 942 (340/340-v)

Isolate for frequency

949/942 = (340+v/340-v)

v= 1.26m/s (speed at which a whistler is moving)