## Astrophysics one year ago Could use a little help, relativity.

1. Astrophysics

A rocket ship of proper length $$l_0$$ travels at constant velocity $$v$$ relative to a frame S. The nose of the ship $$(A')$$ passes the point $$A$$ in S at $$t=t'=0$$, and at this instant a light signal is sent from $$A'$$ to $$B'$$.

2. Astrophysics

Here's my figure |dw:1444376673186:dw| the time $t' = \frac{ l_0 }{ c }$ for the sginal to reach the tail B' of the ship. My question is, at what time $$t_1$$, as measured in S, does the signal reach the tail $$B'$$ of the ship.

3. Astrophysics

|dw:1444376950407:dw|

4. anonymous

oh wait.. no sorry lolz

5. Astrophysics

Yeah, I sort of tried all of this already, I'm not quite sure at this point haha

6. anonymous

But its still fairly simple all you need to do is contact the length and then use classical physics to figure out the time taken..

7. anonymous

contract*

8. Astrophysics

$\tau = \tau_0 \gamma$ I did try that oh..I think it's because this is the first question where I have the frames the other way around so my algebra must be wrong..

9. Astrophysics

$l =\frac{ l_0 }{ \gamma }*$

10. Astrophysics

Figured it out, thanks anyways @Mashy :)