def FE(q1,q2,r):
    ke=8.99E9
    f=ke*q1*q2/r**2
    return f

def FG(m1,m2,r):
    G=6.67E-11
    f=G*m1*m2/r**2
    return f

C=3.0E8
pi=3.1416
G=6.67E-11
ke=8.99E9
e=1.6E-16
h=6.26E-34
hbar=1.05E-34
mu=4*pi*10.E-7
epsilon=8.85E-12
a0=5.29E-11
me=9.1E-31
mp=1.67E-27
Ry=1.1E7
NA=6.02E23
kB=1.38E-23
muB=9.27E-24
ME=6E24
RE=6.38E6