Beam shear forces are dependent on beam moments because the two are not independent of each other. HyperSizer assumes a constant shear force in a beam and a linear variation of bending moment. The constant shear force in a beam is calculated from:

V = ( M(end B) – M(end A) ) / Length

It sounds like you are loading the beam up as a cantilevered beam, therefore, the bending moment on end B would be zero and to get the shear you want, set

M(end A) = - V *Length

So, for a shear force of V = 10 lb on a 30” beam, set M(end A) = - (10) * (30) = -300 lb-in, M(end B) = 0, and the Length to 30”. Analyze, and you should see a V value of 10 lb.

Let me know if you have more questions.