Question

Disused railway line has a length of 300 m. a man puts his ear against one [3] end of the rail and another man hits the other end with a metal hammer, as shown in figure.
(i) sound travels at a speed of 5000 m/s in steel. calculate the time it takes for the sound to travel along the rail.
(ii)the man with his ear to the railway line actually hears two sounds from the
hammer,separated by a short interval. explain why he hears two sounds.

Answer 1

Answer:

(ii) The man with his ear to the railway line actually hears two sounds from the hammer, separated by a short interval. Explain why he hears two sounds. Answer: ... The man hears two sounds one through air and other through railway line made of steel.

Answer 2

Given: Railway line length l= 300m

          speed of sound in steel v= 5000m/s

To Find: Time taken = t

Solution:

Formula used: distance = speed × time

300 = 5000 × t

t = 300/5000

t =0.06 seconds

ii)

• The man heard two sounds from the hammer as the sound waves traveled from both steel (railway line) and air.
• The first sound heard was that from railway tracks, next was when sound waves traveled through the air.
• speed of sound in air = 331 m/s i.e < 5000m/s that in steel therefore the sound waves traveling through steel were first heard.