physics
posted by Melissa on .
The mass of Earth can be calculated using the fact that the weight of an object (in newtons) is equal to the force of gravity between the object and Earth. Given that the radius of Earth is 6.4*10^6m , determine its mass

Hmmm. Several things are missing here.

mg = GmM/R^2
M=gR^2/G,
where
g=9.8 (m/s^2) ,
gravitational constant
G = 6.67•10^11 (m^3•kg^1•s^2)