# I Special relativity of two clocks

1. Jun 5, 2016

### Physgeek64

Why is it that for two clocks that are synchronised in one frame, S, but not in another, S', is there an offset in the time by a factor of $\frac{Lv}{c}$, as measured in S'. Where L is the proper length of the body, as measured in S. I'm confused as to why there is not a factor of $\gamma$ here

Many thanks

2. Jun 5, 2016

### Orodruin

Staff Emeritus
Why do you think there should be a factor $\gamma$? Have you looked at how the relation is derived?

3. Jun 5, 2016

### Battlemage!

I'm pretty sure the offset in time is Lv/c2, not Lv/c (since obviously Lv/c is in units of length).

Also section 11.3 of this link has a problem that comes up with your Lv/c involving synchronized clocks on a train. It has a nice picture too showing the distance the photon must travel, which gives those two factors.

http://www.people.fas.harvard.edu/~djmorin/chap11.pdf

4. Jun 6, 2016

### Physgeek64

How careless of me- I did mean over $c^2$. Funnily enough, this was the book that caused my confusion. I don't feel like he explains it very well. However, I have since worked it out- so all it good.

Thank you for replying though- it's very appreciated :)

5. Jun 7, 2016

### Battlemage!

Haha no it definitely could be clearer, but it does have a good picture I think.