In FR = RPM × T × CL, what does RPM stand for?

• A. Revolutions per minute
• B. Rotations per mile
• C. Radians per minute
• D. Revs per hour

Answer: (A)

RPM is a standard speed unit for rotation, representing revolutions per minute. In the given equation, RPM tells you how many full turns occur each minute, which is the natural way to quantify rotational speed in mechanical contexts. The term revolutions per minute fits exactly: a revolution is a complete turn, and per minute shows the time basis used in this formula.

Rotations per mile isn’t correct because it combines rotation with distance, which isn’t a speed of spin. Radians per minute would be a different way to measure angular velocity, using radians instead of full revolutions. Revs per hour is just revolutions per hour, not per minute, so it doesn’t match the RPM abbreviation.