Why is girl on a swing one of Newtons second law of motion example?
The guy above is dead wrong. No, 2nd law of Newton has to do with external forces acting upon an object, the movement of such object will be affected by the force changing its velocity by the well known equation F = ma where F is the external force, m is the mass of the object and a is the acceleration of the object due to the external force (which is the change of the velocity). In your example the girl on the swing is affected by the gravitational attraction Earth being that the external force, and when you plug in all the information in the simple equation is wrote it turns out that the force affects her movement is such a way that what you see as the final result is the swinging.
