If a train is 100 kilometers away, how much sooner would you hear the train coming by listening to the rails (iron) as opposed t

Question

2 years ago

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If a train is 100 kilometers away, how much sooner would you hear the train coming by listening to the rails (iron) as opposed t

o listening for it standing by the track? In other words, how much faster will the sound travel through the iron rails than through the air? Assume the air temperature is 0°C. Sound will reach you seconds sooner.

Physics

1 answer:

Whitepunk [10] · Answer 1 · 2022-08-28T21:36:37+03:00

From tables, the speed of sound at 0°C is approximately
V₁ = 331 m/s (in air)
V₃ = 5130 m/s (in iron)

Distance traveled is
d = 100 km = 10⁵ m

Time required to travel in air is
t₁ = d/V₁ = 10⁵/331 = 302.12 s

Time required to travel in iron is
t₂ = d/V₂ = 10⁵/5130 = 19.49 s

The difference in time is
302.12 - 19.49 = 282.63 s

Answer: 283 s (nearest second)