# Example 6-1
MKS(N)
m1 = 50 kg
m2 = 70 kg
r = 0.5 m
f = GEarth() * m1 * m2 / r^2

# Example 6-2
MKS(N)
m1 = 2000 kg
me = 5.98e24 kg
re = 6380 km
f2r = 0.25 * m1 * grav()

# Example 6-3
MKS(N,km)
Mm = 7.35e22 kg
Me = 5.98e24 kg
Ms = 1.99e30 kg
rme = 3.84e5 km
fme = GEarth() * Mm * Me / rme^2
rms = 1.5e8 km
fms = GEarth() * Mm * Ms / rms^2
f = sqrt(fme^2 + fms^2)

# Example 6-4
MKS(N)
h = 8850 m
re = 6380 km
r = re + h
me = 5.98e24 kg
gg = Gearth() * me / r^2

# Example 6-5
MKS(N)
re = 6380 km
tt = 1 day
v = 2 * pi() * re / tt
ar = v^2 / re

# Example 6-6
MKS(N)
re = 6380 km
me = 5.98e24 kg
tt = 1 day
r = (Gearth() * me * tt^2 / (4 * pi()^2))^(1/3)
v = sqrt(Gearth() * me / r)

# Example 6-9
res = 1.5e11 m
Te = 1 yr
Ms = 4 * pi()^2 * res^3 / (Gearth() * Te^2)

# Example 6-10
me = 5.98e24 kg
Ms = 2.0e30 kg
res = 1.5e11 m
d = (me / 3 / Ms)^(1/3) * res

# Homework Problems:

TBD