What does a torque wrench measure?

A torque wrench measures the amount of rotational force applied to a fastener. This instrument is crucial in ensuring that fasteners, such as bolts and nuts, are tightened to the appropriate specifications, preventing over-tightening which can lead to stripping or breaking, and under-tightening which can result in fasteners loosening over time. The torque value applies to the specific requirements of different materials and applications, which is critical for achieving desired mechanical properties and safety standards.

The other options do not pertain to what a torque wrench measures. For instance, measuring the length of a fastener would require tools such as calipers or rulers, while measuring the temperature of a mechanical joint would involve thermometers or thermal imaging. Weight measurement involves scales and is unrelated to the torque applied. Thus, understanding the function of a torque wrench specifically highlights its role in precision fastening in mechanical and structural applications.