# General/special relativity-a measurement problem

1. Nov 1, 2012

### ofer

1. The problem statement: all variables and given/known

Describe a Non-Local Expirement that will lead to the conclusion that a body is in fact in a revolving system and not a system of constant acceleration. Non-Local meaning that the expirement uses 2 measurement instruments at 2 different points in space or 1 instrument with a segnificant size. describe what these instruments are and where they are placed.

2. this was given as a final part of a question involving describing the proper time of a body in a revolving system with SR due to gravitational potential. meaning not yet gotten to GR.

3. The attempt at a solution:
I tried to think of this something like the moon revolving around the earth, where the moon is the revolving system captured in the gravitational pull of the earth. somewhere 2 measurement instruments must be placed to variffy that the moon is revolving around the earth and not being accelerated by some other constant force.
i'm really lost though on how to do this. i have a pretty good notion that an accelerometer should be used somewhere, or maybe clocks and something to do with proper time diffrences between the systems... really lost/

appriciate any kind o help.
thanks.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 1, 2012

3. Nov 1, 2012

### ofer

hmmm, so you meen a viewer outside of the rotating frame of reference would observe the coriolis effect.
thats true' although it feels kind of like cheating, because one could say that a viewer outside the system would actually see the object rotating..
how would he measure it though?

4. Nov 1, 2012

### HallsofIvy

Staff Emeritus
It's NOT a matter of an "external observer". If you and another person are moving at a constant velocity, throwing a ball back and forth would be no different that if you we both stationary (relative to the "outside"). But if you are accelerating, because acceleration is NOT "relative" strange things may happen. In particular, if you and the other person are rotating around a point between you, throwing a ball toward the other person, you and the other person will see that ball curve away from the other person.