A speeder tries to explain to the police that the yellow warning lights on the s

Question

A speeder tries to explain to the police that the yellow warning lights on the side of the road looked green to her because of the Doppler shift. How fast would she have been traveling if yellow light of wavelength 570 nm had been shifted to green with a wavelength of 558 nm? (Note that, for speeds less than 0.03c, Equation 21.32 will lead to a value for the change of frequency accurate to approximately two significant digits. Accordingly, please enter your response to 2 significant digits.)
m/s

Explanation / Answer

fobs = {(1+v/c)/(1-v/c)}^0.5 * fsource

(1+v/c)/(1-v/c) = (fobs / fsource)2

                        = (570/558)2

                        = 1.04347

>>>> 1+v/c = 1.04347 * (1-v/c)

>>>> 1+v/c = 1.04347 - 1.04347*v/c

>>>> (1+1.04347)v/c = 1.04347-1

>>>> 2.04347*v/c = 0.04347

>>>> v/c = 0.04347/2.04347

>>>> v = 0.0213 c

>>>> v = 0.0213*3e8

>>>> v = 0.064 * 10^8 m/s

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