Forces are measured in newtons because the newton (N) is the standard unit of force in the International System of Units (SI). Here's why this is the case:

* Newton's Second Law of Motion: This law states that the force acting on an object is directly proportional to its acceleration and its mass. Mathematically: F = m * a

* Force (F): Measured in newtons (N)

* Mass (m): Measured in kilograms (kg)

* Acceleration (a): Measured in meters per second squared (m/s²)

* Definition of the Newton: The newton is defined as the force required to accelerate a 1 kilogram mass at a rate of 1 meter per second squared. This definition directly ties the unit of force to the fundamental units of mass and acceleration, making it a consistent and practical unit.

* SI System: The SI system is designed to be a coherent and standardized system of measurement. The newton, being derived from the fundamental units of the SI system, fits seamlessly into this framework.

Why not other units?

While other units of force exist (e.g., pound-force, dyne), the newton is the preferred unit in scientific and engineering contexts due to its direct connection to the SI system and its ease of use in calculations.