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.
Confidence votes 51. The most notable difference is that composite toe shoes don't set off metal detectors and are generally lighter than steel toe shoes. A steel toe shoe has a piece of steel inside the tip (about 2 1/2 inches) to protect the toes from being crushed if a heavy object falls on the foot.