Why is the maximum speeds (rpm or m/s) for cutting wheels so important?

Different sizes tools eg. angle grinders, run at different speeds. For example, a 125mm 5″ angle grinder runs at almost twice the speed of a 230mm 9″ angle grinder. All bonded abrasive wheels such as cutting and grinding wheels will explode through centrifugal force if they are run at a speed higher than what they are rated at. Accidents through the misuse of angle grinders injure and kill more people than any other power tool in Australia.