A cyclist stops beside a large, flat wall on a warm summer afternoon when the air temperature is 30∘C. He produces a sharp whistle and listens for the echo.
(a) The speed of sound in air varies with temperature according to the relation v=331+0.6T, where T is the temperature in ∘C and v is in m/s. Calculate the speed of sound in air at 30∘C.
(b) Using your answer from part (a), find the minimum distance between the cyclist and the wall required for him to hear a distinct echo.
(c) If the wall is actually 50m away, compute the time interval between the whistle and the echo that will reach the cyclist.