 #1
greg_rack
Gold Member
 363
 79
 Homework Statement:

At what speed should a plane move to make the roar of its turbines double in frequency for the observers who are in front of it in its path?
Does the result depend on the frequency considered?
RESULT: [vs = vw/2]
 Relevant Equations:

DOPPLER effect for a moving source heading to a steady receiver: ƒr=ƒs*1/[1(νs/νw)]
CAPTION: "r = receiver", "s = source", "w = wave"
I had many attempts on trying to solve this one, but I got always stuck in the problemsolving part: how do I manage to find the sourcespeed from the Doppler formula, in an analytical way, and then reach to the resultformula?
Anyway, I'm pretty sure the only formula needed to solve this problem is the one i attached, which links the receivedfrequency to the source one, and the source/wave speed.
Anyway, I'm pretty sure the only formula needed to solve this problem is the one i attached, which links the receivedfrequency to the source one, and the source/wave speed.