from numpy import pi

h = 0.0025          # W / cm^2*K

class Bar1():
    def __init__(self):
        self.k = 0.5            # W / cm*K
        self.r = 0.1            # cm
        self.A = pi*self.r**2   # cm^2
        self.P = 2*pi*self.r    # cm

class Bar2():
    def __init__(self):
        self.k = 0.5            # W / cm*K
        self.r = 0.1            # cm
        self.A = pi*self.r**2   # cm^2
        self.P = 2*pi*self.r    # cm

        self.alpha = ((h*self.P)/(self.k*self.A))**0.5