A train standing at the outer signal of a railway station blows a whistle of frequency 400 Hz still air.
A train standing at the outer signal of a railway station blows a whistle of frequency 400 Hz still air.The train begins to move with a speed of 10 m s-1 towards the platform. What is the frequency of the sound for an observer standing on the platform?(sound velocity in air = 330 m s-1)
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Given: v0 = 400 Hz
Velocity of train, v1 = 10 m/s
Velocity of sound in air, va = 330 m/s
Apparent frequency when source is moving
vapp = \(\frac{v_a}{(v_a-v_t)}\)v0
= \(\frac{330\times400}{(330-10)}\)
vapp = \(\frac{825}{2}\) = 412.5 Hz
vapp = 412.5 Hz
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