Gravitation equations and expressions - gravitational field strength

AI Thread Summary
The discussion centers on two homework questions regarding gravitational field strength. The first question asks for an algebraic expression for gravitational acceleration (g) at a distance r from a planet's center, treated as a point mass M. The correct formula is g = GM/r^2, where G is the gravitational constant. The second question seeks the formula for gravitational field strength at the planet's surface, which also uses the same expression with r being the planet's radius. Clarification confirms that replacing m with M in the equation is valid.
dory
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Homework Statement


i have 2 questions on my holiday homework that I am not 100% sure on they are:

Homework Equations



1) write down an algebraic expression for g at a distance r from the centre of the planet. The planet can be treated as a point mass of magnitude M as its centre

AND

2) write down a formula for the gravitational field stength g at the surface of the planet of mass M

The Attempt at a Solution


is one of them g=Gm/r^2
i am so confused
 
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is one of them g=Gm/r^2
If you replace m with M, yes.
 

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