A 0.25kg pendulum bob is suspended from a 0.60m long, light rod. A horizontal spring with force constant 45Nm−1 is attached to the bob at the pivot height and is relaxed when the rod hangs vertically. The bob is pulled sideways until the rod makes a 15∘ angle with the vertical and released from rest. Neglect air resistance. Determine the speed of the bob as it passes through the lowest vertical position.