As measured from the Earth, a spacecraft is moving at speed 0.80c ...

[Metfan725]

As measured from the Earth, a spacecraft is moving at speed 0.80c when it releases a probe at speed 0.60c relative to the spacecraft in a forward direction. What would be the speed of the probe as measured from the Earth?
 a. 0.70c
  c. c
  b. 0.81c
  d. 0.95c

Question 2

As measured from the Earth, a spacecraft is moving at speed 0.80c toward a second spacecraft moving at speed 0.60c back toward the first spacecraft. What is the speed of the first spacecraft as viewed from the second spacecraft?
 a. 0.81c
  c. 0.38c
  b. 0.95c
  d. 0.20c

[momtoalll]

Answer to Question 1

D

Answer to Question 2

B