Two trains on separate tracks move toward one another. Train 1 has a speed of 140 km/h and train 2 a speed of 65.0 km/h. Train 2 blows its horn, emitting a frequency of 500 Hz. What is the frequency heard by the engineer on train 1?
i have the equation F'=F(velocity of sound +/- speed of receiver/speed of sound +/- speed of source of sound) but im sitll not getting the right answer....
2007-03-11 11:22:52 · 4 answers · asked by kbeauty 4 in Science & Mathematics ➔ Physics
Alright, start with this
Train 2 is the source of sound having a frequency of 500 Hz. and if it's moving towards train 1 that means it's postive so + 65 km/h . Now the observer on train one is also moving towards train 2 so + 140 km/h. Now you have the find what speed the sound travels through air during 1 km/h so
v= 345 m/s / 1000m ( to get it to km) * 3600 sec ( to have 1 hour) = 1240 km/h
now finally you can use your equation up there making sure to put 1240 km/h in v rather than 345m/s.
Good luck Hope this helps
2007-03-11 12:13:34 · answer #1 · answered by Anonymous · 1⤊ 0⤋
i'm no longer specific what precision degree your professor seems for. in spite of the indisputable fact that Doppler's effects isn't that easy to apply to longitudinal waves. the approach you had is strictly perfect in basic terms for transverse waves. For longitudinal waves the gadgets are shifting in direction of one one greater on the fronts of the waves yet a procedures from each and each distinctive on the rears of the waves. This motives a skewed sinusoidal wave inspired on a microphone. This skewness represents a composite wave envelope that's additionally decomposed by way of skill of Fourier strengthen into to get a collection of harmonics.
2016-10-01 23:12:46 · answer #2 · answered by ? 4 · 0⤊ 0⤋
I am not sure what precision level your professor looks for. But Doppler's effect is not that simple to apply to longitudinal waves. The formula you had is strictly correct only for transverse waves. For longitudinal waves the objects are moving towards one another on the fronts of the waves but away from each other on the rears of the waves. This causes a skewed sinusoidal wave impressed on a microphone. This skewness represents a composite wave envelope which may be decomposed by Fourier transform to get a series of harmonics.
2007-03-11 12:10:13 · answer #3 · answered by sciquest 4 · 0⤊ 0⤋
equation looks correct since both objects are moving and are heading towards each other.
Did your remember to convert km/h to m/s?
2007-03-11 12:50:06 · answer #4 · answered by John 5 · 1⤊ 0⤋