He also devised his own laws of motion that include 1) heavier objects will fall faster, the speed being proportional to the weight and 2) the speed of the object that is falling depends inversely on the density object it is falling through (e.g. density of air). He also stated that, when it comes to violent motion (motion of an object when a force is applied to it by a second object) that the speed that object moves, will only be as fast or strong as the measure of force applied to it. This is also seen in the rules of velocity and force that is taught in physics classes today. These rules are not necessarily what is described in physics today but, they are mostly similar. It is evident that these rules were the backbone for other scientists to revise and edit his beliefs.