Question

an enemy spaceship is moving toward your starfighter with a speed of 0.4c, as measured in your reference frame. The enemy ship fires a missile toward you at a speed of 0.7c relative to the enemy ship. If you measure the enemy ship to be 8.0 x 10^6 km away from you when the missile is fired, how much time, measured in your frame, will it take the missile to reach you ?

Answer 1

5s