When a steam train of 34 m/s sounds a steam whistle for 10 seconds from the point 1700 m before a station, for how many seconds can the steam whistle be heard at the station?
The speed of sound shall be 340 m/s.
Answer
Nine seconds
Solution
It takes 5 seconds for the beginning sound to reach the station according to the calculation of 1700m / 340m/s = 5 seconds.
Since the train runs 340m for ten seconds (34m/s × 10 = 340m), it takes 4 seconds for the last sound to reach the station.
From the beginning it is 10 + 4 = 14 seconds after.
Therefore the time heard at the station is 14 - 5 = 9 seconds.
The speed of sound shall be 340 m/s.
Answer
Nine seconds
Solution
It takes 5 seconds for the beginning sound to reach the station according to the calculation of 1700m / 340m/s = 5 seconds.
Since the train runs 340m for ten seconds (34m/s × 10 = 340m), it takes 4 seconds for the last sound to reach the station.
From the beginning it is 10 + 4 = 14 seconds after.
Therefore the time heard at the station is 14 - 5 = 9 seconds.
