In summary,

1. Wherever there is a transverse shear force V in a beam, the bending moment will not be constant.

2. If a beam segment has unequal moments acting on it, there will be an imbalance in the resultant axial forces produced by the bending moments.

3. To satisfy equilibrium for any particular portion of the beam segment, a shear force acting in the axial direction must exist on internal surfaces of the beam.

4. The magnitude of the internal shear force depends upon the portion of the total cross-sectional area that is being considered.

Finished