Question

A spaceship is moving in a straight line away from Earth at 0.80c, measured relative to Earth. It launches a missile that moves away from the spaceship in the forward direction at 0.60c, relative to the ship. Relative to Earth, what is the speed of this missile?
A. c
B. greater than c but less than 1.4c
C. 1.4 c
D. greater than 0.80c but less than c

Answer 1

Answer: c- 1.4 c

Explanation:

Velocity of the space ship v = 0.80 c velocity of the missile v ' = 0.60 c

then the velocity of the missile measured by observer is v + v'

0.80c + 0.6c =1.4c