Mass of the Earth
We can use the equation: g = G*Mearth/Rearth2
to solve for Mearth since we know
g = 9.8 m/s2 (from our lab experiment),
G = 6.67 x 10-11 Nt-m2/kg2 (from precise gravity force experiments), and
Rearth = 6,400 km (since we know the circumference of the earth = 25,000 miles).