def calculate_velocity_resistances(f1, velocities):
    """
    Calculates forces function of velocity [N].

    :param f1:
        Defined by dyno procedure [N/(km/h)].
    :type f1: float

    :param velocities:
        Velocity vector [km/h].
    :type velocities: numpy.array | float

    :return:
        Forces function of velocity [N].
    :rtype: numpy.array | float
    """
    return f1 * velocities
