What is the rim speed measured in ft/min on the outside of a pulley?

Rim speed, also known as peripheral speed, refers to the linear speed of the outer edge of a rotating pulley or wheel. It is calculated using the formula: rim speed (ft/min) = (π × diameter × RPM), where diameter is in feet and RPM is the revolutions per minute of the pulley.

In the context of this question, if the correct answer is 4000 ft/min, it indicates that when you perform the calculation using the specific diameter and RPM of the pulley being analyzed, the resulting speed at the outer rim will be 4000 feet per minute. This value is significant in the realm of power transmission as it determines the efficiency and capability of the pulley in conveying motion or power to other components in a mechanical system.

Higher rim speeds can be beneficial for certain applications, allowing for the movement of energy with less slip, but it also requires careful consideration of the materials and the design of the pulley to ensure safety and prevent excessive wear or failure. Understanding rim speed is essential for millwrights and engineers when selecting and designing pulley systems for various applications.