Relative to Earth, spaceship A travels at \(0.732 c_{0}\) away from Earth, and spaceship B travels at \(0.914 c_{0}\) toward Earth along the same straight line.

(a) How fast does A move according to an observer aboard \(\mathrm{B}\) ?

(b) At \(t=0\) the two ships are separated by \(4.5 \times 10^{10} \mathrm{~m}\) in the Earth reference frame. At what instant \(t\) do they pass each other according to an observer at rest on Earth?