What does a torque wrench measure?

A torque wrench is designed specifically to measure the amount of torque applied to a fastener, such as a bolt or screw. Torque is essentially a force that causes an object to rotate around an axis, and it is measured in units such as pound-feet or Newton-meters.

When using a torque wrench, the user can set a specific torque value, and the tool produces a signal (audible click, for instance) to indicate when the desired torque level has been reached. This ensures that fasteners are tightened to the proper specifications, which is critical for safety and performance in mechanical applications. Over-tightening or under-tightening can lead to component failure or disengagement.

In contrast, other options do not align with the function of a torque wrench. For example, measuring the angle of rotation involves different tools like a protractor or angle gauge. The length of gaps between surfaces would typically require calipers or gap gauges, and assessing the compression rate of a spring pertains to different measuring instruments such as a spring scale. Therefore, the capacity of a torque wrench to specifically measure the torque applied to a fastener is what makes this option the correct choice.