How fast would you have to drive in order to see a red light as green?

Question

take lambda= 630nm for red and lambda 530nm for green, can anyone help me for the answer? i have two but im not sure which is it or if they are rigth, one of my answers is 5.66 to the 6 m/s and the other is-4.76 to the 7 m/s

Answer 1

theres no such thing as negative velocity.  its just positive velocit with a different vector.  i don't wanna do the math, buit id say its the first one.

Answer 2

assuming the red light is stationary you need to travel 100nm in the time it takes to wiggle once.  time taken to wiggle once is about 3e8/6.3e-7 so call it 5e-14. 100nM is 1e-7 so 4.76e7 m/s

Answer 3

You are on a futile quest, no amount of speed will give you that result.

Answer 4

If you've had enough drinks, all traffic lights look green. Hick!

However, I suppose you're looking for a special relativity answer.

Gamma = 1/sqrt(1-(v^2/c^2)) You want to know what speed yields

gamma = 630/530 = 1.189.

1/gamma = .841 = sqrt(1-(v^2/c^2))

1 - (v^2/c^2) = .841^2 = .7077

v^2/c^2 = 1 - .7077 = .2923

v/c = .5406

v = .5406 c = 180,340 km/sec.