A uniform, 4.0 kg square, solid wooden gate with sides measuring 1.5 m hangs vertically from a frictionless pivot at the center of its upper edge. A 1.1 kg raven flying horizontally at 5.0 m/s flies into the center of the gate and bounces back at 1.5 m/s in the opposite direction. What is the change in momentum of the raven?
