Pangaea refers to All Land
Answer:
21.7 seconds.
Explanation:
Woman's velocity relative to train (23 m/s - 22.4 m/s) = 0.6 m/s
Distance woman wants to travel = 13m
To find how long she will take to move 13m relative to the train, take the distance she wants to travel divided by her velocity relative to the train.
(13m)/(0.6 m/s) = 21.6667 seconds or 21.7 seconds.
Therefore, it will take the woman 21.7 seconds to move 13m.
This is a Doppler effect. Generally, if you move to a frequency source, you would detect an increase in frequency and when you move away from a source you would detect a decrease.
For this question, before you pass them, you are actually approaching them, so you would hear a higher frequency than the constant 300 Hz they are playing at.
Using the condensed formula:
f ' = ((v <u>+</u> vd)/(v <u>+</u> vs)) * f
Where: vd = Velocity of the detector.
vs = Velocity of the frequency source.
v = Velocity of sound in air.
f ' = Apparent frequency.
f = Frequency of source.
v = 343 m/s, vd = detector = 27.8 m/s, vs = velocity of the source =0. (the flautists are not moving).
f = 300 Hz.
There would be an overall increase in frequency, so we maintain a plus at the numerator and a minus at the denominator.
f ' = ((v + vd)/(v - vs)) * f
f ' = ((343+ 27.8)/(343 - 0)) * 300
= (370.8/343)* 300 = 324.3
Therefore frequency before passing them = 324.3 Hz.
Cheers.
