- #1
harujina
- 77
- 1
Homework Statement
Two train whistles have frequencies of 180 Hz in air (v = 344 m/s). When one train is at rest sounding its whistle, a beat frequency of 2 Hz is heard from the moving train which is sounding its whistle as well. What is the moving train's speed if it is approaching the station?
Homework Equations
fbeat = l fo - f1 l
fo = fs (v + vo / v - vs) ; [source is approaching the observer]
fo: observer
fs: source
The Attempt at a Solution
v = 344 m/s
fs = 180 Hz
fo = 182 Hz [fo = fbeat + fs; = 2 Hz + 180 Hz]
vo = 0
vs = ?
fo = fs (v + vo / v - vs) ; [source is approaching the observer]
I'm trying to rearrange this formula to isolate vs but for some reason I can't.
Where do I start... I've tried everything.
And sorry about all the questions, I'm having some significant trouble with this unit in physics...