Hydraulics

shear force
example
Shearing forces occur when a perpendicular force is applied to static material (in this case a beam). Think of a knife cutting through a carrot. Imagine the beam is the carrot and a point load is a knife. As the knife applies a downward force, it cuts (or shears) the carrot.

Shear force is an internal force in any material which is usually caused by any external force acting perpendicular to the material, or a force which has a component acting tangent to the material.