Gravitational acceleration/ centripetal

[Maiia]

Homework Statement

Given: G = 6.67259 × 10−11 N · m2/kg2
A satellite moves in a circular orbit around Earth at a speed of 3160 m/s.
Find the satellite’s altitude above the surface of Earth. Answer in units of m.

I'm not sure how to do this without the mass of Earth..don't you need it to plug it into:

R^3orbit/ T^2 = GMplanet/ 4pi^2

 

[LowlyPion]

Homework Statement

Given: G = 6.67259 × 10−11 N · m2/kg2
A satellite moves in a circular orbit around Earth at a speed of 3160 m/s.
Find the satellite’s altitude above the surface of Earth. Answer in units of m.

I'm not sure how to do this without the mass of Earth..don't you need it to plug it into:

R^3orbit/ T^2 = GMplanet/ 4pi^2

Mass 5.9736×10²⁴ kg

http://en.wikipedia.org/wiki/Earth