"The design of any structural or mechanical member requires an investigation of the loading acting within the member in order to be sure the material can resist this loading. These internal loadings can be determined by using the method of sections." p 323

AXIAL FORCE
A FORCE APPLIED PARALLEL TO THE SYMMETRY AXIS OF AN OBJECT

BENDING MOMENT
A MOMENT, TORQUE OR TWISTING FORCE THAT MAY CAUSE AN OBJECT TO DEFORM OR BEND.

FORCE
A PUSH OR A PULL

FORCE

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.

NORMAL
IN MECHANICS, NORMAL OFTEN MEANS PERPENDICULAR OR AT RIGHT ANGLES TO A SURFACE OR A DIRECTION. NORMAL CAN ALSO MEAN NOMINAL OR AVERAGE.

NORMAL FORCE
A FORCE THAT IS PERPENDICULAR TO A SURFACE OR THE DIRECTION OF MOTION OF A SYSTEM.

SHEAR

SHEAR FORCE

TORSION

TORSIONAL MOMENT