i was just about to sit down and start writing the "program" for my accelerometer & leostick when i found myself in some sort of dimensional anomaly, & now i don't know if i'm coming or going! my problem is this - if "g" is a unit of acceleration (approx 9m/sec/sec) and an object is at rest on the surface of the earth it is said to be experiencing 1g, but hang on it's not moving! on the other hand if it is falling towards earth it is accelerating at approx 9m/sec/sec but it is said to be experiencing 0g. can you see where i'm coming from? or maybe where i've been? please help me as my project is getting nowhere fast.

cant help thinking if newton had been born 100 years earlier he may have written " 2g or naught 2g that is the question..." instead of his laws of motion.

## Heisenberg

### Re: Heisenberg

Well, "moving" depends on your frame of reference - if you were falling from your roof the ground would appear to be moving, and more importantly Accelerating toward you - at 1g too. I could bore you with details, but all you really need to understand is that gravity is pulling the sensor down (the whole sensor, including the bit inside which measures acceleration) while the desk it is sitting on is pushing against the housing of the sensor, so the apparent acceleration is 1g straight up.

Any other external force will add to this force - which is a 3 dimensional vector - so to calculate acceleration relative to the earth, work out which way is up and subtract 1g.

Sounds simple eh?

Any other external force will add to this force - which is a 3 dimensional vector - so to calculate acceleration relative to the earth, work out which way is up and subtract 1g.

Sounds simple eh?

### Re: Heisenberg

thanks for the enlightenment drake. p.s. the ground hasn't moved for me for quite some time!