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Real World Physics Problems Newsletter - Newton's 2nd Law, Issue #29
April 04, 2016

Newton's Second Law

Newton's second law is a familiar term to many people, especially those who have studied physics. For the study of mechanics and bodies in motion it is the equation from which many other equations come from. The equation is simply, F = ma, where F is the force acting on a particle, m is the mass of the particle, and a is the acceleration of the particle. This equation is proven only by experimental tests. It is not derived from anything else. It is a fundamental relationship used to describe the nature of motion. It is as fundamental as Relativity and Newton's law of gravitation.

The essence of F = ma is that it mathematically describes the relationship between quantities which are actually very different from each other. For instance, force is a quantity you can "feel", acceleration is a quantity that you can "see", and mass is a quantity used to describe how much of something there is.

In some respect, F = ma reveals different dimensional aspects of the universe. It reveals the presence of forces, either through the non-contact forces of magnetism and gravity, or through contact with other objects. It reveals the presence of matter. And it reveals the space-time nature of the universe through the acceleration term.

The lesson here is that fundamental physics equations can reveal insight into our universe upon closer examination. They give a mathematical relationship between different physical quantities, which arise from distinct features of the universe.

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