Final answer:
An impact test measures the toughness of a material, which is its resistance to fracturing under an impact load. Hardness and ductility are distinct properties, with hardness being the resistance to abrasion and ductility the ability to stretch under tension.
Step-by-step explanation:
An impact test is primarily used to determine the toughness of a material, which is its ability to absorb energy and plastically deform without fracturing. Toughness provides a measure of a material's resistance to fracture when subjected to a sudden, forceful load or impact. This is different from hardness, which is a material's ability to resist abrasion or scratching, often measured on the Mohs' scale, and ductility, which is the material's ability to deform under tensile stress. Hardness may influence how an element is used, such as gold being relatively soft compared to much harder elements like tungsten. The term tensile strength refers to the breaking stress that will cause permanent deformation or fracture of a material, which is a different property than those assessed by an impact test.