1

I was wondering, if two cars (A and B) are going at different velocities let's say A=90km/h, B=80km/h then if we add the two speeds we get 170km/h meaning they are relative to each other.

But if one of the cars were going at the speed of light and the other at 90km/h it's impossible to add them because nothing can go faster than the speed of light meaning they are/aren't relative.?

So my question is: is light relative?

user555076
  • 19

1 Answers1

4

velocities don't add up like A + B = C. This is only approximately true in the limit of every day perception. You have to consider your coordinate frames relative to each other if you approach relativistic (meaning a fraction of the speed of light) velocities.
$s = \frac{u + v}{1 + \frac{u v}{c^2}}$ would be the added velocity s of two objects moving relative to each other with velocity u and v respectively. For more information see Lorentz transformation

rtime
  • 557
  • 3
  • 17