What is a profilometer used for?

A profilometer is specifically designed to measure the surface topography of a material, which includes assessing the surface roughness. This instrument provides valuable information about the smoothness or texture of a surface by capturing its profile in terms of peaks and valleys. By tracing the surface, a profilometer quantifies parameters such as average roughness and other related metrics, which are crucial in various manufacturing and machining processes where surface finish is critical for the performance and aesthetics of a part.

The other choices involve different measurements unrelated to the purpose of a profilometer. Measuring a part's weight pertains to mass assessment, while determining tensile strength involves assessing how much force a material can withstand without breaking. Similarly, calculating hardness relates to the resistance of a material to deformation or indentation. These activities utilize distinct tools and methodologies that are not applicable to the function of a profilometer.