from numpy import *
%pylab inline

Populating the interactive namespace from numpy and matplotlib

6.2

U = 3.6e5
eps = 8.854e-12
v = 10
d = 1e-6
def capacitor_area(u,v,d):
    return 2*u*d/v/v/eps
print "You need %.2e m^2 plate area"%capacitor_area(U,v,d)
print "That is %.2e meters high!"%(d*capacitor_area(U,v,d))

You need 8.13e+08 m^2 plate area
That is 8.13e+02 meters high!

6.3

mu = 1.26e-6
l = 2.
r = 1.
B = 10
print "Outward force: %.2e N"%(pi*l*r*B*B/mu)

Outward force: 4.99e+08 N