(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Two spaceships fly toward a space station as shown in the figure. Relative to the station, spaceship A has speed 0.8c. Relative to the station, what speed is required of spaceship B such that its pilot sees A and the station approach B at the same speed?

(a) 0.40c (b) 0.50c (c) 0.60c (d) 0.70c (e) 0.80c

2. Relevant equations

u = u' + v/(1+(v)(u')/(c^2)), the relative velocity formula for speeds near the speed of light

L = L0/ϒ, where ϒ = 1/(1-(v/c)^2))^(1/2), maybe

3. The attempt at a solution

I know that I can use the relative velocity equation to figure the relative speed of A according to B by substituting the speed of B in for v in the relative velocities equation. I want to get the relative speed of A to be the same speed for which the space station is approaching B, but I can't seem to derive a formula exactly for that. I'm confused about what I have to work with here.

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# Homework Help: Relative velocities in special relativity

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