The speed of sound depends on the medium that the waves pass through, and is a fundamental property of the material. The first significant effort towards the measure of the speed of sound was made by Newton.
These meet ASTM safety standards and are suitable for most professions. Composite. Many safety boots are nonmetallic-instead of steel or aluminum, they are reinforced with a composite-material steel toe boots, usually made with thermoplastic polyurethane (TPU) or similar materials.
Features of an alloy toe: 1  An alloy toe is made from aluminum, titanium or a combination of lightweight metals. 2  Alloy toes are 30%-50% lighter than steel toes. 3  The toe box can be larger with an alloy toe because an alloy toe can be made a little thinner than other safety toes.