5. A metal rod which is 1.2 m long has a rectangular cross-section of area 2.0 cm. It hangs vertically and an object of mass 30 kg is attached to its lower end. (a) If the object's weight stretches the rod by 2.0 mm, determine the Young's modulus of the metal. (b) The object is then pulled downward and released. What is the angular frequency and period of the subsequent simple harmonic motion?