Spec. Relativity: time differences.

[Ekpyrotic]

Revising for Jan test; it's become apparent that my spec. rel. knowledge isn't watertight. I have a particular problem with questions in the following form.

 

Anna is in a ship traveling at 0.8c; Bob is at relative rest. (At rest both the ships measure 100m). So, Anna whizzes past at 0.8c when the two ship's tails are next to each other the tail's clocks both read 0. Note: There is also a clock in Anna's ship's nose; Bob's ship has a camera next to Anna's ship's nose.

 

(a) Where is Anna's nose relative to Bob's ship?

 

This stuff is no problem. Lorentz factor = [math]\frac{1}{\sqrt{1-0.8^2}} = \frac {5}{3}[/math]

 

So, [math]\frac{5}{3}*100=60m[/math]

 

(b) What time does the camera record for Anna's clock that is in the nose. (I have problems here)

 

I know that the clock should read an earlier time; but don't know how to calculate that time.

 

Thanks.

 

Ripiptickakee! Got it, ridiculous question on my part.

Edited December 17, 2008 by Ekpyrotic
multiple post merged