F=ma

Besides being the mathematical formulation of Newton's Second Law, $F=ma$ is the name of the preliminary exam in the road for selection for the USA IPhO team.

F=ma is Newton's second law of motion, stating that the more force put in, the faster a given object will accelerate. F is force, M is mass, and A is acceleration. Another way to put it is:

The vector sum of the forces acting upon an object is equal to the mass of the object multiplied by the acceleration of the object. Its use is quite simple. Given some information of two of the three, you can calculate the third. For example, if you have the acceleration and force exerted onto an object, you can calculate the mass of the object.

Other way of putting the law:

$\mathbf{F} = \frac{\mathrm{d}\mathbf{p}}{\mathrm{d}t} = \frac{\mathrm{d}(m\mathbf v)}{\mathrm{d}t}$

The law was originally written in Latin, in the book Philosophiae Naturalis Principia Mathematica. The original Latin reads:

''Lex II: Mutationem motus proportionalem esse vi motrici impressae, et fieri secundum lineam rectam qua vis illa imprimitur.''

This translates to:

''Law II: The alteration of motion is ever proportional to the motive force impress'd; and is made in the direction of the right line in which that force is impress'd.''

Newton's Laws are normally applicable to everyday life, unless you are dealing with special relativity, high speeds, really small scales, etc.

$F=ma$ means that the total force that an object has is equal to its mass times its acceleration.

Newton's Second Law of Motion states that " The force of an object is directly proportional to the rate of change of momentum of the object." Mathematically it means that : $\frac{dp}{dt}$

And, since mass is a constant physical property and the rate of change of velocity is acceleration, we can write this as, F = ma

This was stated in Sir Isaac Newton's famous book Principia and this equation forms the base of Classical Mechanics.