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Table below tabulates the values of Wk˛ for commonly used cross sections.

Table compiled based on References 1 and 2.

Nomographs on subsequent pages facilitate conversion of different units of inertia. A table shows actual inertia values for discs of different diameters.

Equivalent Inertia 
Must be considered when inertia has to be reflected to a shaft which rotates at a different speed.

Torque
If a body of inertia I_G is accelerated at a constant angular acceleration q radians/sec˛ the necessary constant torque is
       T = I_G · q.......... lb.ft                                                    (3)

If the acceleration speeds up the load D N RPM within t seconds then the angular acceleration can be expressed as:


where Dw is the change of angular velocity in radians/sec. 
Substitution into (3) yields

T16