Kepler's Third Law: Homewor Help

[No2]

Homework Statement

A spy satellite is located one Earth radius above the surface of the Earth. What is its period of revolution?

ans. 1.5 x 10^4 s

Homework Equations

I'm trying to use the kepler's constant: k = T^2/R^3

The Attempt at a Solution

 

[rock.freak667]

Kepler's law can be derived by equating the force of attraction with centripetal force

i.e. GMm/r²=mω²r

or GM/r³=(2π/T)²

So what would be your constant or proportionality 'k' if you rearrange to get T²/r³?

 

[tiny-tim]

Welcome to PF!

Hi No2! Welcome to PF!

(try using the X² icon just above the Reply box )

I'm trying to use the kepler's constant: k = T^2/R^3

Unless you're using the Moon, what T are you going to compare with?

Use the ordinary Newton's law of gravitation to find the force of gravity as a multiple of g (that's our g, not G ! ), and https://www.physicsforums.com/library.php?do=view_item&itemid=27"