Consider a thin rod of mass 3.5 kg, length 4.8m and uniform density. The rod is pivoted at one end on a frictionless horizontal pin. The rod is initially held in a horizontal position but eventually allowed to swing down, What is its angular acceleration at the instant it makes and angle 45 degrees with the horizontal. The acceleration of gravity is 9.8 m/s^2. Answer in units of rad/s^2