Which formula is used to calculate RPM?

The formula used to calculate RPM (revolutions per minute) is based on the relationship between frequency and rotational motion. The correct formula reflects how frequency, measured in hertz (Hz), relates to rotational speed.

The option provided as the correct answer, which is 60 x F (N/2), correctly takes into account that frequency (F) is the number of cycles per second, but to convert this into RPM, you would multiply by 60 to find out how many revolutions occur in a minute. The term (N/2) likely refers to a specific context where the number of cycles or revolutions is divided based on a setup involving a gear or pulley system, where only half of the total cycles contribute to the effective rotational speed being measured.

In this context, multiplying the frequency by 60 gives the number of revolutions per minute, making this formula applicable for determining RPM, especially in mechanical systems that involve gearing.

The other options, while they present relationships involving either frequency or speed, do not appropriately align with the standard calculation required to derive RPM from a given frequency in the way that the correct answer does. For example, while 30 x Hz may appear relevant for certain applications, it doesn't universally represent RPM calculations