Physics Problem: Satellites in Circular Orbits

1. Oct 3, 2004

shawonna23

A satellite orbits a planet at a distance of 3.70*10^8 m. Assume that this distance is between the centers of the planet and the satellite and that the mass of the planet is 3.93*10^24 kg. Find the period for the moon's motion around the earth. Express the answers in earth days.

I tried using this equation: T= (2pi)(r)^(3/2) divided by square root of GMe

2. Oct 3, 2004

vsage

I know this sounds like a lot of work but if your equations aren't working right and nobody else gives an answer (I'll delete this if someone does) you can just set centripetal force equal to the gravitational force between two bodies (the mass of the moon cancels out so you don't need it but put it in as a constant first) and solve for the velocity. This velocity can then be used to calculate the period. Edit I would like to point out if you pull this off you will have derived the equation you were told to use.

3. Oct 3, 2004

Sirus

Shawonna, show us your work using that formula, cuz it should work.

4. Oct 3, 2004

shawonna23

Physics Problem: Satellites in Circular Orbits

Here is my work:

T= 2*pi*(3.70*10^8)^(3/2) DIVIDED BY (6.67*10^-11)*(3.93*10^24)

i keep getting the wrong answer.

5. Oct 3, 2004

TenaliRaman

U sure the formula is right??
i have this feeling u missed a root somewhere
prolly sqrt(G)??

-- AI

6. Oct 3, 2004

vsage

I think Tenali is right. I don't see sqrt() in any of your work.

7. Oct 3, 2004

Janus

Staff Emeritus
If you used the formula correctly, you should have got an answer in the order of 32 days.