1 Nicolaas Vroom | A rigid rod with 8 clocks, preface | Wednesday 13 November 2019 |

2 maluw...@gmail.com | Re :A rigid rod with 8 clocks, preface | Wednesday 13 November 2019 |

3 Jose Gonzalez | Re :A rigid rod with 8 clocks, preface | Wednesday 13 November 2019 |

4 Mitch Raemsch | Re :A rigid rod with 8 clocks, preface | Wednesday 13 November 2019 |

A rigid rod with 8 clocks, preface.

4 posts by 4 authors

https://groups.google.com/g/sci.physics.relativity/c/JloAn7hTmsg/m/-KD8HiE3AgAJ
keywords = The behaviour of a clock, Special relativity

Consider two rods, with each 8 clocks, moving along the x-axis.
Observations reveal that the distance between the two rods changes.

1) The first question is: can both rods be at rest?
The answer is: one can be considered at rest but not both.

When that is the case something must have happened in the past to create this situation.

That is why we start from the situation that both rods are at rest and give one rod a power boost to get it moving. We now have two rods: rod 1: at rest, and rod 2: moving.

2) The next question to ask is: Is it possible by means of an experiment to decide if a rod is at rest or moving.

To answer that question I will try to describe a certain number of experiments as detailed as possible.

The first thing we perform is clock synchronization for all the clocks of
both rod 1 and rod 2.

(Clock synchronisation is discussed in the posting: A rigid rod with 8 clocks)
Next, you give all the engines of rod 2 a boost.
Thereafter When a clock at rest meets a moving clock they can be compared.
The results show that the moving clock runs slower than a clock at rest.
You can repeat the same experiment in the opposite direction and the result
is the same: the moving clock runs slower than a clock at rest.

This is an important result because it means that the behaviour of a moving clock is symmetric in both directions, starting from a state at rest.

3) The next question to answer is this also true when we start with a
moving rod?

The first thing we do is to make two copies of rod 2 and we call them
rod 3 and rod 4.
The second thing we do on both rods we perform a clock synchronization.
Thereafter we give the engines part of rod 4, a boost in the same
direction as original for rod 2.

4) You cannot compare the clock rate of rod 2 with rod 3 because their speed
is the same.

However, you can compare both rod 2 and rod 3 with rod 1 when they meet
because their speed is different.
The results are: that all the readings of rod 1 are the same, all the
readings of rod 2 are the same but lower and all the readings of rod 3
are different.

In fact, if you assume that both rod 2 and rod 3 move towards the right
than the reading of clock #1 (towards the left) is the lowest and the
reading of clock #8 (towards the right) is the highest.
This is in agreement with the physical idea that clock #1 is reset first
and clock #8 the latest.

This is a very important physical implication. The moving clocks part of rod 3
and 4 don't run individual simultaneous (compared with rod 1 and rod 2)

5) This has also a physical consequence when we give the engines, part of
rod 4 a boost, immediate after the received reset signal or based on a certain
clock reading: the engines will not fire simultaneously.

The has physical consequences because this unequal firing will cause internal
forces, which in this case will try to decrease the length of the rod.

The consequence is that in fact, you should not use a rigid rod.

6) Consider rod 2. This is the same situation as discussed in item (2) above.
When the engines are fired for the first time. the rod will move in a certain
direction and the moving clocks will run slower as the clocks at rest.
Fire the engines again and the clocks will run slower again.

This is called: the decision situation or moment.
At this specific moment, you can do two things.

You can fire the engines again and the clocks will run even slower.
Or you can first reverse the direction and then fire the engines.
In that case, the clocks will start to run faster.

This behaviour is called asymmetric.

7) Consider rod 3. Better is to copy rod 3 and this becomes rod 4.
We first perform a clock synchronization. Now again we have to make a
decision. We can do two things:

7.1) We can fire the engine in the same direction as originally.
The result is, that the clock will start to run slower.
This can be demonstrated by comparing rod 4 with rod 3 when they meet.
7.2) We could also fire the engines in the opposite direction.
This shows the same behaviour as in item(6): The clocks will start to run faster.
This again can be demonstrated by comparing rod 4 with rod 3.

For more detail see:

https://www.nicvroom.be/Article_Review_Moving%20Bodies_Appendix2.htm
Specific goto Reflection 5: Is the behaviour of a moving clock symmetric?

8) What can we learn from this?

Generally speaking that the behaviour is different if the rod is at rest or moving.
In almost all cases the rod is moving.
(At least that is my opinion...)

Hopefully, this makes this whole set of experiments simpler.

Nicolaas Vroom.

On Wednesday, 13 November 2019 11:32:57 UTC+1, Nicolaas Vroom wrote:

> |
Consider two rods, with each 8 clocks, moving along the x-axis.
Observations reveal that the distance between the two rods changes. 1) The first question is: can both rods be at rest? The answer is: one can be considered at rest but not both. |

Yes, this is an answer; another answer is: of course they both can be considered. We can also answer that it depends on ... [a lot of
possibilities here].

Applying common sense the limits are fuzzy. Rejecting common sense
there is no limits.

Nicolaas Vroom wrote:

> | Consider two rods, with each 8 clocks, moving along the x-axis. Observations reveal that the distance between the two rods changes. 1) The first question is: can both rods be at rest? The answer is: one can be considered at rest but not both. |

You can't, state that, unless a third part Observer. Try again.

How are rigid rods free to contract? No. Contracted atoms lead to chemistry gone awry.

Mitchell Raemsch