Answer:
Step-by-step explanation:
Let the velocity of lander with respect to earth be v .
In relativistic mechanism the expression for relative velocity is
v_r =

Given u = .6c , v_r = .8 c
Substituting the values
.8c =

.8c-.48v = v - .6c
v = .946c
b )
Distance in terms of time = .2 ly
In relativistic mechanism , expression for relativistic time is given by the following relation
t =

Substituting v = .946c
tâ = .2
t =

.2 / â.1050
= .62 ly
distance to the Earth at the time of lander launch, as observed by the aliens will be .62 ly.