Answer:
The frequency of the sound note as heard = 429 Hz
Explanation:
The frequency of sound waves as heard from a distance for a sound wave coming towards one at v₀ m/s and whose real frequency is f₀ is given by
+f = f₀/[1 - (v₀/v)]
+f = frequency of sound as heard from the distance away = ?
f₀ = real frequency of sound = 401 Hz
v₀ = velocity at which the sound source is moving towards the reference point = 23.0 m/s
v = velocity of sound waves = 343 m/s
+f = 401/[1 - (23/343)]
+f = 429 Hz
