What is it that makes a window break when a baseball hits it? Is it Kinetic energy, Momentum, or Pressure? Also, how does that relate to and differ from force? Not the force that causes a change in acceleration, but deforms an object. When an object is being twisted, the Stiffness and Strength of an object have to be overcome. How is using kinetic energy, momentum or pressure to break something relate to and differ from using a force to deform an object?