def sim2RealUnits(force_sim=None, torque_sim=None):
    """
    Converts forces and torques in simulation units to real world units. 

    Inputs: 
    force_sim : scalar value of force in simulation units
    torque_sim : scalar value of torque in simulation units

    Outputs: 
    force_real_pN : scalar value of force in [pN]
    torque_real_pNnm : scalar value of torque in [pN nm]
    """
    if force_sim is not None:
        # force_sim units are (5.24 * 10^-25) kg * (8.518 * 10^-10) m / (3.03 * 10^-12 s)^2
        # want to convert to kg * m / s^2 = N
        # then convert to pN = 10^-12 N
        
        # force real = force sim * (5.24 * 10^-25) kg * (8.518 * 10^-10) m * 1 / ((3.03 * 10^-12)s)^2 
        # force_real = force_sim * (1 / (5.24 * 10**(-25))) * ((1 / (8.518 * 10**(-10)))) * ((3.03 * 10**(-12))**2)
        force_real = force_sim * (5.24 * 10**(-25)) * (8.518 * 10**(-10)) * (1 / ((3.03 * 10**(-12))**2))

        # force_real pN = force real * (1 pN / 10^-12 N)
        force_real_pN = force_real * (1 / (10**(-12)))
    else:
        force_real_pN = None

    if torque_sim is not None: 
        # torque_sim units are (5.24 * 10^-25) kg * (8.518 * 10^-10)^2 m / (3.03 * 10^-12 s)^2
        # want to convert to kg * m^2 / s^2 = Nm
        # then convert to pN nM = 10^-12 N 10^-9 m

        # torque real = torque sim * (5.24 * 10^-25) kg * ((8.518 * 10^-10) m)^2) * 1 / ((3.03 * 10^-12)s)^2 
        torque_real = torque_sim * (5.24 * 10**(-25)) * ((8.518 * 10**(-10))**2) * (1 / ((3.03 * 10**(-12))**2))

        # torque_real pN = torque real * (1 pN / 10^-12 N) * (1 nm / 10^-9 m)
        torque_real_pNnm = torque_real * (1 / (10**(-12))) * (1 / (10**(-9)))
    else: 
        torque_real_pNnm = None

    return force_real_pN, torque_real_pNnm