Answer Happy

7. (a) 4 points A very fast spaceship travels at 0.8c through our solar system. How long does it take to cover the distance between the sun and earth (8.3 light minutes) according to an observer on Earth? How long does it take to cover that distance as measured by the crew on board? (b) 2 points Assume a particle traveling at a speed vhas a momentum p. If the same particle travelling at twice the speed has a momentum of 3p what is the speed v? (c) 2 points A spaceship is traveling past you at a speed of 0.5c. You measure its length to be 70 m, what is the spaceship's length in its rest frame? (d) 2 points Two spaceships are approaching earth from opposite directions, each moving with a speed of 0.45c relative to earth. How fast do the spaceships move relative to each other?