F=ma
Newton's second law states that force is proportional to what is required for an object of constant mass to change its velocity. This is equal to that object's mass multiplied by its acceleration. We use Newtons, kilograms, and meters per second squared as our default units, although any appropriate units for mass (grams, ounces, etc.) or velocity (miles per hour per second, millimeters per second2, etc.) could certainly be used as well - the calculation is the same regardless.
