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Author Topic: Gravity on Earth !....is it changing ?  (Read 1613 times)

Offline neilep

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Gravity on Earth !....is it changing ?
« on: 09/07/2008 14:58:20 »
Dearest All,


Gravity is my all time favourite force that retains my body here and stops me from going into orbit !

I luff it, ewe luff it...Bungee Rope manufactures luff it !


Look...here's some acting on the progeny between a domestic cat and a Walrus !



Nice eh ?


With the growing population and building of stuff....does the little we do affect the  strength of Earths gravity ?.......Pending a collision with a big thing.......does anything have an affect on Earths gravity ?.....

You see, I'm losing weight and I need to know this to factor in the gravitational differences between May this year (2008)....when I started ....and a year from now !

Thank ewe all for your help.


Neil
Concerner of Gravity !


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Offline syhprum

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Gravity on Earth !....is it changing ?
« Reply #1 on: 09/07/2008 16:03:45 »
The force of gravity acting upon you on the surface of the Earth depends only upon the mass of the Earth and your distance from the centre.
The mass of the earth is to all effects unchanging although there are tiny changes due to the upswelling of magma such as we see from volcanoes but the effect is tiny.
the rotation of the Earth leads to variation of your weight according to your latitude but the actual component due to gravity only varies due to the change in distance from the centre as the earth is not truly spherical.
 

Offline RD

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Gravity on Earth !....is it changing ?
« Reply #2 on: 09/07/2008 17:44:38 »
With the growing population and building of stuff....does the little we do affect the  strength of Earths gravity ? .
The number of humans and their artifacts do not add to the mass of the Earth.


You see, I'm losing weight and I need to know this to factor in the gravitational differences between May this year (2008)....when I started ....and a year from now !
The force of gravity is dependent on the mass of the the two bodies (Earth&you) and the distance between them.
As Syhprum mentioned the Earth is an oblate spheroid : you would weigh more at the poles than on the equator.

Quote
the Earth's equatorial bulge (itself also caused by centrifugal force) causes objects at the equator to be farther from the planet's centre than objects at the poles. Because the force due to gravitational attraction between two bodies (the Earth and the object being weighed) varies inversely with the square of the distance between them, objects at the equator experience a weaker gravitational pull than objects at the poles.

In combination, the equatorial bulge and the effects of centrifugal force mean that sea-level gravitational acceleration increases from about 9.780 mĚs-2 at the equator to about 9.832 mĚs-2 at the poles, so an object will weigh about 0.5% more at the poles than at the equator.
http://en.wikipedia.org/wiki/Earth's_gravity
« Last Edit: 09/07/2008 17:52:51 by RD »
 

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Gravity on Earth !....is it changing ?
« Reply #2 on: 09/07/2008 17:44:38 »

 

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