A spring scale is commonly used to measure what?

A spring scale is specifically designed to measure force, typically in units such as newtons or pounds. The principle behind a spring scale involves Hooke's Law, which states that the force exerted by a spring is proportional to its extension or compression within its elastic limit. When an object is hung or placed on the scale, the weight of that object causes the spring to stretch, and the scale indicates the force due to gravity acting on the object.

This focus on measuring force makes the spring scale an essential tool in various applications, particularly in physics experiments where understanding the interaction of forces is crucial. In contrast, the other options—length, mass, and velocity—are measured using instruments designed specifically for those purposes, such as rulers for length, balance scales for mass, and speedometers or timers for velocity. Each of these other measurements relies on different principles and mechanisms, which highlights why the spring scale is exclusively suited for force measurement.