And indeed this is the most famous equation in physics, establishing an equivalence between energy and mass. Knowledgeable scientists will tell you no. Students of science and engineering devote half of the time of a classical mechanics course studying and learning how to apply this equation. Cast in this way, Newton's second law provides the response of a body of mass m to a force F .
Forces are things that cause changes in motion.
Such a change is called acceleration and is denote by the symbol a . A body is undergoing acceleration if it changes its speed or changes its direction of motion. When you push something, you are inflicting a force upon it. Hence, if you strike a vase with your hand knocking it over, the vase feels a force and undergoes a change of motion. Clearly, a vase lying on its side has undergone a change in state.