Physics Help Forum Little g without Big G

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 Mar 10th 2019, 10:22 AM #1 Junior Member   Join Date: Mar 2019 Posts: 4 Little g without Big G Anyone know how to find the gravity of a planet without using the gravitational constant?
Mar 10th 2019, 11:50 AM   #2

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 Originally Posted by JDDuncan Anyone know how to find the gravity of a planet without using the gravitational constant?
By "gravity" I presume you are referring to "acceleration due to gravity?"

Nope. I suppose there many sophisticated method you could employ but all of them are based on Newton's theory of gravitation and all would eventually depend on G.

The simplest equation would be: $\displaystyle g = \dfrac{GM}{r^2}$.

Think of it this way: If G were bigger we'd expect that the force on an object would be larger than it is now. So g would be larger as well. So there has to be a connection between the two.

-Dan
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 Mar 10th 2019, 05:34 PM #3 Junior Member   Join Date: Mar 2019 Posts: 4 Yes, the acceleration of gravity. Thanks.
Mar 10th 2019, 06:53 PM   #4
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 Originally Posted by topsquark Nope. I suppose there many sophisticated method you could employ but all of them are based on Newton's theory of gravitation and all would eventually depend on G. -Dan
Would it be big news if someone did find a way?

 Mar 10th 2019, 08:00 PM #5 Senior Member   Join Date: Aug 2010 Posts: 403 What would be wrong with determining g experimentally and determining the mass of the planet from that? topsquark likes this.
Mar 10th 2019, 09:59 PM   #6
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 Originally Posted by HallsofIvy What would be wrong with determining g experimentally and determining the mass of the planet from that?
There’s nothing wrong with that. I’m just asking to see what ways we have.

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