On 27/05/2014 20:31, Cory Smelosky wrote:
On Tue, 27 May 2014, Eric Smith wrote:
> On Tue, May 27, 2014 at 11:41 AM, Dave <dave.g4ugm at gmail.com> wrote:
>
>> Will have a proper look when I am back from having my mass checked....
>> (They call it weight watchers but really its the MASS we are
>> interested in)
>>
>
> Do you routinely undertake any activities such that there isn't a very
> strong correlation between your mass and weight?
Several of my activities may result in the correlation being perhaps
slightly less strong than one might imagine, but in general when
stationary its pretty strong...
However it is the mass I am interested in. After all my fatness is
measured by the Body Mass Index or BMI...
When I climb stairs as Gravity obeys the inverse square law at the top
my weight will have decreased by more than the loss of Mass from energy
conversion. Not by much..
I recently visited Peru and reached the dizzy heights of 4700mtrs, at
the height I would expect the change to be measurable, although from
this page:-
https://uk.answers.yahoo.com/question/index?qid=20130827162749AAcPfU9
it looks like even at the top of Everest I would only be about 1lb
lighter, so I guess at 4700mtrs only a few ounces lighter. In fact I
don't actually need to change altitude. The force of gravity varies from
place to place depending on the thickness of the crust.
Probably get a bigger difference as I also travel up and down in lifts
due to Newtonian physics...
Looking at this Gravity isn't quite constant...
http://earthobservatory.nasa.gov/Features/GRACE/page3.php
so perhaps at the top of Everest the extra mass of the mountain restores
the correlation...
Then there are tides. The show that the gravitational force of the moon
and sun change the apparent gravitational force...
But again as the ground also experiences a tidal variation does that
compensate for or exaggerate the changes due to change in altitude....
http://en.wikipedia.org/wiki/Earth_tide
http://en.wikipedia.org/wiki/Gravimeter
Very high, so my wife says...
--
Dave
G4UGM