Force gauge
Test units of force measurements are most commonly newtons or pounds. The peak force is the most common result in force testing applications. It is used to determine if a part is good or not. Some examples of force measurement: door latch, quality of spring, wire testing, strength ... but more complicated tests can be performed like peeling, friction, texture.
Hooke's law
In SI units, displacements are measured in meters (m), and forces in newtons (N or kg·m/s). Therefore, the spring constant , and each element of the tensor , is measured in newtons per meter (N/m), or kilograms per second squared (kg/s).