A long thin wooden pole is supported at either end atop two water glasses. A swift impulsive blow breaks the pole at it's center without managing to knock over the cups and spill a single drop. How is it possible? I am breaking it against the inertia of the pole, Swinging the metal bar as fast as I can with a quick hit would cause a quick downward acceleration on the wooden pole. But, since the wooden pole has a certain amount of inertia, it can't withstand the sudden acceleration force and so instead of being moved downward it simply breaks. As the pole breaks, the downward force is now acting as a torque, which now causes the two smaller pieces to rotate around their new respective centers of gravity of mass, turning them away from the cups of water and so they remain upright.. If I were to push down on the stick slowly, there would be enough time to allow for the force to be "felt" on the cups and would surely cause them to fall over. The explanation lies in that the force applied to the pole causes the two new pieces to rotate away from the supporting cups keeping them intact.