Clock of observers

1. Dec 1, 2013

Hepic

We have three observers. The A is in earth,B is into a car that runs with big speed,C is out of galaxy.

All observesr see that their clock runs normal. A will see that clock of B run slower,and B will see the same for A.

1)
Logically, C will see A's and B's clock run slower from his clock,but which clock will run slower? A's or B's (I think A's,because has more speed,I am right?)

2)
And from the opposite,who from both(A,B) will see C's clock run slower?(I think again A,due of speed).

I am correct to 1) and 2)

Thanks!!!

2. Dec 1, 2013

Mentz114

What do you mean by 'see' in this

If you mean 'by visual contact', then clocks moving away appear slower and approaching clocks appear faster.

3. Dec 1, 2013

Hepic

That for observer A,clock of B run slower,and for B,clock of A run slower from his clock.

4. Dec 1, 2013

Mentz114

Sure, but this is not a directly observable physical effect. It appears when either time is converted from its rest frame coordinates to the moving frame coordinates.

5. Dec 1, 2013

Staff: Mentor

You still have to specify C's velocity relative to the other two before we can answer the question. Just because he's a looooong ways away doesn't mean he cannot be at rest relative to one, the other, or neither.
(In special relativity, that is. In the general relativity case, we have to be a lot more careful about specifying C's state of motion).

6. Dec 1, 2013

Hepic

C is standing about A and B.

7. Dec 1, 2013

Staff: Mentor

What does that mean?

8. Dec 1, 2013

Staff: Mentor

C cannot be at rest relative to both A and B. They're moving relative to one another, so anything at rest relative to one is moving relative to the other.