At the start of your throw of a 5.6-kg bowling ball, your arm is straight behind you and horizontal. Your arm is 0.64 m long, has a rotational inertia of 0.48 kg⋅m², and has a mass of 3.5 kg with its center of mass 0.28 m from your shoulder joint. Determine the rotational acceleration of your arm at the start of your throw if the muscle is relaxed. Express your answer to two significant figures and include the appropriate units.