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## Main Question or Discussion Point

**F=mv^2/r and Geosynchronouse orbits? Help Guys!**

I’m having a mental block in understanding why geostationary satellites stay in the same place and don’t change orbits or simply fall out of the sky.

I may be using inaccurate information so please vet any and all suppositions I make here.

Using the formulas I found at this web site

http://liftoff.msfc.nasa.gov/academy/rocket_sci/orbmech/formulas.html

I begin with determining the radius for a circular geosynchronous orbit the semi-major axis is given and it turns out to be 42168 Kilometers.

Now, I am assuming that if I calculate the Centrifugal Force on an object in geosynchronous orbit at this distance from the Center of the earth it should equate to the Gravitational force the earth exerts on it.

The formula I remember for Centrifugal force is F=mv^2/r

F= force

m= Mass

v=velocity

r=Radius

so an arbitrary 1 kilogram mass orbiting at r=42168 kilometer distance from the center of the earth traveling at 2(PI)r/24= 11039.56 kilometers /hour around the earth should have a gravitational force equal to the centrifugal force imposed on it by its orbit. Using the above formula F=mv^2/r, is equal to 2890.15 kilograms!

Does the earth impose a gravitational force of over 2890 kilograms on a 1 kilogram object at 42168 kilometers away? I must be doing something or many things wrong! Maybe the formulas or even the premise of the question is wrong.

Please guys help me out.

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