<p>Ok I can’t solve this problem and I don’t know why. I totally understand how to use the Doppler effect for light, but Lon-Capa keeps telling me my answer is wrong, and I have no idea what I am messing up on it. Any help or the answer you got would be greatly appreciated, and I will see if the computer likes that answer. Thanks!</p>
<p>How fast would a motorist have to be traveling for a yellow (l = 591 nm) traffic light to appear green (l = 550 nm) because of the Doppler shift? </p>
<p>(I was using f '=f(1+u\c)</p>
<p>ummm…not allowed on CC…but okay…</p>
<p>you’re dividing c by the wavelength to use as frequency, right?</p>
<p>Yes I’m getting the frequency that way-</p>
<p>Its just my stupid homework thats not even for a grade, but I would like to find out the answer before my test tomorrow, in case there is a problem like it</p>
<p>Lon-Capa is the worrsssst!</p>
<p>make sure you’re using the right wavelength for the original frequency (591) and because it’s blueshifting make sure your velocity is negative</p>
If you have trouble with the Lon CAPA you can visit loncapaedu.com.