# Question: an observer at rest on the earth observes two spacecraft...

###### Question details

An observer at rest on the Earth observes two spacecraft moving
toward one another. Spacecraft 1 travels to the right at a velocity
of 0.71 c relative to the observer. Spacecraft 2 travels to the
left at a velocity of 0.71 c relative to the observer. What is the
velocity of Spacecraft 1 relative to Spacecraft 2 (give your answer
in terms of “c”)? **Make sure that you draw a diagram and
that you label S, S’, u _{x}, u_{x’}, and
v.** Also, remember that velocity is a vector.