Choose a real world situation, such as diving off a diving board, rocket propulsion, or birds flying, and select a motion within that situation that does not occur in a straight line, and is set in motion by the interaction of two objects. Motion that does not occur in a straight line indicates that more than one force is acting on the object and they are responsible for what you are seeing. Try to identify the forces that are causing the motion you selected. Describe how Newtons third law applies to that motion. Since the forces are equal and opposite, be sure to account for size and directions of the motion of the two objects before and after the interaction.