Register to reply

Time Sync Problems

by whereisnomar
Tags: sync, time
Share this thread:
whereisnomar
#1
May28-11, 09:06 AM
P: 2
In this link, the website talks about synchronizing clocks on a moving train. But I have a few questions about it:

1) Why are you allowed to add ct+vt on the left-hand side of the first equation below the picture of the train? I thought one of the main tenants of Special Relativity was that you can't add velocities (or I'd assume distances) without taking into account the dilation/ contraction of that quantity.

2) What would happen if you stopped the train, and then looked at what the clocks say? Would they be synchronized or not? I understand that the train would enter a noninertial reference frame, which would change how they behave, BUT wouldn't both clocks be affected equally... so who is right once the train is stopped- the person who says they're synchronized, or the person who says they're not?

THANK YOU SO MUCH!
Phys.Org News Partner Science news on Phys.org
NASA team lays plans to observe new worlds
IHEP in China has ambitions for Higgs factory
Spinach could lead to alternative energy more powerful than Popeye
ZealScience
#2
May28-11, 09:33 AM
P: 346
Quote Quote by whereisnomar View Post
In this link, the website talks about synchronizing clocks on a moving train. But I have a few questions about it:

1) Why are you allowed to add ct+vt on the left-hand side of the first equation below the picture of the train? I thought one of the main tenants of Special Relativity was that you can't add velocities (or I'd assume distances) without taking into account the dilation/ contraction of that quantity.

2) What would happen if you stopped the train, and then looked at what the clocks say? Would they be synchronized or not? I understand that the train would enter a noninertial reference frame, which would change how they behave, BUT wouldn't both clocks be affected equally... so who is right once the train is stopped- the person who says they're synchronized, or the person who says they're not?

THANK YOU SO MUCH!
It didn't say that velocity is added, ct+vt is the distance wich had been through a length contraction.

Though I didn't learnt much of it, I don't think that the clock would be synchronized. Because according to the rest frame it is not synchronized even when the train is still moving, for different frames have different synchronization.
schaefera
#3
May28-11, 09:47 AM
P: 208
So at what point would the person on the train see them leave synchronization, then?

ZealScience
#4
May28-11, 09:52 AM
P: 346
Time Sync Problems

Quote Quote by schaefera View Post
So at what point would the person on the train see them leave synchronization, then?
I think just when the train changes speed. Look at the time of rear and front, they depend on c+v and c-v, so when v changes time would change. Synchronization means when the two times are equal, but if they are equal at one v they gotta be different when v changes.
schaefera
#5
May29-11, 10:20 AM
P: 208
Any other ideas?


Register to reply

Related Discussions
Sync function Calculus & Beyond Homework 4
How do I sync a pen drive to a folder? Computers 0
Clocks out of Sync (Special Relativity) Introductory Physics Homework 7