How do i calculate the surface gravity of a planet?

[Souper]

So i'm playing Universe Sandbox 2, and i remember the original Ubox having a feature that tells you surface gravity.

However, Ubox2 does not have this, and, giving only planetary radius and mass, how can i calculate surface gravity with only those 2 parameters?

[Tarrow]

the equation would be

Where G is the gravitational constant (6.67x10^-11), m₁ is the mass of the planet and r is the radius of the planet. Use a value of 1 for m₂ and that'll give you how many newtons of force act on a 1kg mass.

Using the figures for earth (roughly) m₁ would be 5.98x10²⁴kg, r would be 6.38x10⁶m.

Thereforre F for an m₂ value of 1 would be = (6.67x10^-11 x 5.98x10²⁴) / (6.38x10⁶)²

F = 9.799 N

(fairly accurate, depending on the quality of the planet mass / radius information you have)

Edited February 10, 2015 by Tarrow

[Bill Phil]

Shouldn't this be in science labs?

Take out mass 2 in that equation and you get gravity in meters per second per second...

[Souper]

OH WAIT SORRY

Looks like i somehow mixed up the science labs with space lounge.

MODS! FIX THIS PLEASE!

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