Printable View
A pursuit spacecraft from the planet Tatooine is attempting to catch up with a Trade Federation cruiser. As measured by an observer on Tatooine, the cruiser is traveling away from the planet with a speed of 0.6c. The pursuit ship is traveling at a speed of 0.8c relative to Tatooine, in the same direction as the cruiser. What is the speed of the pursuit ship relative to the cruiser?
I believe I answered this on another board and said that I agreed with the result you gave their. But perhaps we were both looking at this incorrectly (I'm not a physicist!). We both were doing this as. But relative the cruiser, Tatoine has a velocity of -.8c. So the "sum" of speeds should be
.
Hey, guys.
I think the numerator should be reversed:
is the velocity of sprinter ship relative to Tatooine and
is the velocity of Tatooine relative to the cruiser ship.
If that were the case, the sprinter ship would see the cruiser ship with speed +.38c and it would not be gaining!
The velocity is measured relative to the cruiser, so it should be gaining.
Actually, Doc Al on physicsforums spotted the sign error.Quote:
Originally Posted by HallsofIvy
I believe I answered this on another board and said that I agreed with the result you gave their. But perhaps we were both looking at this incorrectly (I'm not a physicist!). We both were doing this as