Two tiny iron spheres are welded to a homogenous metallic antenna. The spheres have a mass of 25 g each, whereas the antenna is 1 m long and has a mass of 250 g. Assume that the size of the spheres is small compared to the length of the antenna. Calculate the moment of inertia of this system about a fixed axis parallel to the antenna. The distance between the axis and the antenna is 15 cm.