The unit used to measure force is the newton (N). It is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. The newton is a fundamental unit in the International System of Units (SI) and is crucial for various applications across physics, engineering, and other fields. The formula \( F = ma \) (force equals mass times acceleration) illustrates how force is quantified in terms of mass and the resulting acceleration, providing a clear understanding of its application.