# Gravitational Force Problem?

• Rbethell16
In summary: It's the distance from the center of the Earth.In summary, the Earth's radius is 6.86 e6 m and its mass is 5.98 e24 kg. A satellite is floating in space at a point where the Earth's gravitational acceleration is 3.2 m/s^2. To find the distance above the Earth's surface, we can use the formula Fg = Gmm/r^2, equating the gravitational force of attraction to the centripetal force. The mass of the satellite does not need to be known as it cancels out in the equation. Solving for the distance, we get R = √(GM/3.2), where R is the distance from the center of

## Homework Statement

The radius of the Earth is 6.86 e6 m and the mass of the Earth is 5.98 e24kg. There is a satellite floating in space at a point where the Earth's gravitational acceleration is 3.2 m/s^2.

How far above the Earth's surface is the satellite?

Fg = Gmm/r^2

## The Attempt at a Solution

I know I need to find Fg - at least I think. But I don't know how to start...

Rbethell16 said:

Fg = Gmm/r^2

## The Attempt at a Solution

I know I need to find Fg - at least I think. But I don't know how to start...

The gravitational force of attraction provides the centripetal force. So you need to equate Fg and Fcentripetal (which you can just write as ma for this case).

rock.freak667 said:
The gravitational force of attraction provides the centripetal force. So you need to equate Fg and Fcentripetal (which you can just write as ma for this case).

ma - ok, I have the acceleration, but I get confused as to which "m" i am using. My problem is the intuition with formulas

Wow I reread the problem and I am extra confused. How do I figure out the mass of the shuttle?

Rbethell16 said:
Wow I reread the problem and I am extra confused. How do I figure out the mass of the shuttle?

You don't need it! if you have

ma= GMm/r2

an 'm' (the mass of the shuttle) cancels out Ahhh so 3.2 = G(5.98e24)/R^2. Then solve for R?

Rbethell16 said:
Ahhh so 3.2 = G(5.98e24)/R^2. Then solve for R?

Yes, but be aware of what that R is.