Finding intervals of sound

Question

Fred strikes a steel train rail with a hmmer at a frequency of 2.50 Hz and wilma puts her ear to the rail 1.0 km away.

a) How long after the first strike does wilma hear the sound

b) what is the timeinterval between the successive sound pulses she hears?

Answer 1

steel train rail; speed of sound in steel ~ 6000 m/s

a) distance = 1000 m

time = 1000 / 6000 m/s = 0.166 s

b) frequency of 2.50 Hz

     If each strike is a "sound pulse", then there is a pulse every 0.4 sec.

1Hz = 1/s, so 1 / 2.5 1/s = 0.4 s

Answer 2

b)

T=1/f = 1/2.5

a)

t =d/v=1000 m/ (speed of sound in steel)