most important equations in physics
The Most Important Equation in Physics. Almost everyone has heard of the equation E = mc2. And indeed this is the most famous equation in physics, establishing an equivalence between energy and mass. But is this the most important equation in physics? Knowledgeable scientists will tell you no. The most important equation in physics is F = ma, also known as Newton's second law of mechanics. It governs the behavior of everything that is seen and unseen on Earth and in the cosmos -- from the trajectory of a baseball to the motion of a planet.