The rate at which the hanging mass increases in falling speed. Measured in meters per second squared.

The rate at which the bar (or the bar with two masses) is increasing in rotational speed. (i.e. how quickly it is getting faster) Measured in radians per second squared.

The rate at which the hanging mass falls. Measured in metres per second.

The rate at which the bar (or the bar with two masses) is rotating. Measured in radians per second.