1.
GMm/r^2=(4mπ^2r)/T^2
GM=(4π^2r^3)/T^2
GMm/R^2=mg
g=(4π^2r^3)/(R^2*T^2)
2.
GMm/R^2=mv^2/R
v=√(GM/R)
=[2πr√(r/R)]/T