When asked following question i just got one attempt on answer in km.
A is a spaceship leaving
planet *earth* going west at 170 000 km/s and
B is a spaceship leaving
planet *earth* going east at 170 000 km/s.
When A is 170 000 km away from planet *earth* it fires a laser towards
B.

wrote:
When asked following question i just got one attempt on answer in km.
A is a spaceship leaving
planet *earth* going west at 170 000 km/s and
B is a spaceship leaving
planet *earth* going east at 170 000 km/s.
When A is 170 000 km away from planet *earth* it fires a laser towards
B.
Questions:
1. How far away from planet earth is B when laser hit B.

0 L 2L 2L+vt
|----------|----------|-----|
A E B

L = 1.7*10^8 m
v = 1.7*10^8 m/s
Light hits B at the time t. (t=0 when light emitted)
t = (2L+vt)/c
t = 2L/(c-v) = 3.4/(3-1.7) = 2.6 s
B's distance from Earth when light hits = L+vt = 615 000 km

Everything relative to Earth frame.

Paul