"The moment of inertia of an area originates whenever one has to compute the moment of a distributed load that varies linearly from the moment axis. A typical example of this kind of loading occurs due to the pressure of a liquid acting on the surface of a submerged plate." p 498

AXIS
AN IMAGINARY LINE THAT SERVES AS A CENTER OF ROTATION OR A REFERENCE LINE

INERTIA
A PROPERTY OF A BODY THAT RESISTS ANY CHANGE IN MOTION. FOR TRANSLATION MOTION, MASS IS A MEASURE OF THE BODY INERTIA. IT IS HARD TO CHANGE THE STATE OF MOTION OF A HIGH MASS OBJECT. FOR ROTATION, THE MOMENT OF INERTIA OF A BODY IS A MEASURE OF BODY INERTIA.

MOMENT
A FORCE APPLIED TO AN OBJECT AT SOME DISTANCE FROM THE ROTATION AXIS THAT MAY CAUSE THE OBJECT TO ROTATE. THIS IS THE SAME AS A TORQUE. THE MOMENT IS CALCULATED AS THE PRODUCT OF A FORCE TIMES THE DIRSTANCE OF ITS POINT OF APPLICATION FROM THE AXIS OF ROTATION.

MOMENT OF INERTIA
THE RESISTANCE OF A BODY TO ANY CHANGE IN ROTATIONAL MOTION. THIS IS CALCULATED AS A PRODUCT OF MASS TIMES THE SQUARE OF THE DISTANCE FROM THE MASS TO THE AXIS.

PARALLEL

PARALLEL AXIS THEOREM
A HANDY RESULT THAT HELPS CALCULATE THE MOMENT OF INERTIA FOR A RIGID OBJECT AROUND ANY AXIS ONCE YOU KNOW THE MOMENT OF INERTIA OF THE OBJECT AROUND ONE AXIS. THE AXES USED MUST BE PARALLEL TO EACH OTHER.

POLAR MOMENT OF INERTIA