A spaceship traveling at 0.50c away from Earth launches a secondary rocket in the forward direction at 0.50c relative to the spaceship.As measured by Earthlings,how fast is the secondary rocket moving away from Earth?
A)0.90c
B)0.50c
C)0.80c
D)0.70c
E)c

Question

Quizplus · Accepted Answer

We can use the relativistic velocity addition formula to solve this problem:
v = (u + v') / (1 + uv'/c^2)
where:
u = velocity of the spaceship = 0.50c
v' = velocity of the secondary rocket relative to the spaceship = 0.50c
c = speed of light

Substituting the values, we get:
v = (0.50c + 0.50c) / (1 + 0.50c x 0.50c/c^2) = 0.80c

Therefore, the secondary rocket is moving away from Earth at 0.80c, as measured by Earthlings.

A Spaceship Traveling at 0