A 5 cm long rod of aluminum alloy 2024-T3, with a diameter of 1.28 cm, is tested in tension to failure. The yield and tensile strengths are found to be 345 and 485 MPa, respectively, and the total elongation is 18%. Calculate the load at yielding and the load at fracture. Assuming that necking occurs when the specimen has elongated uniformly by 15%, calculate the instantaneous diameter at the onset of necking and the true stress at the onset of necking.