Two manned satellites approach one another at a relative velocity of 𝑣=0.210 m/s intending to dock. The first has a mass of 𝑚1=4000 and the second a mass of 𝑚2=7500. If the two satellites collide

Question

Two manned satellites approach one another at a relative velocity of 𝑣=0.210 m/s intending to dock. The first has a mass of 𝑚1=4000 and the second a mass of 𝑚2=7500. If the two satellites collide elastically rather than dock, what is their final relative velocity?

I don't understand exactly how what the term relative velocity means in this problem and how I can use that given velocity term?

Answer 1