Description of Problem 513: The problem statement shows a sketch of a cantilever beam. The beam is subject to a distributed load of constant magnitude in a section of its length. You are asked to obtain the internal shear force at a certain location within the beam.
Analysis of Problem 513: This kind of problem is most easily handled with the method of sections: You make a "cut" of the beam at the location of interest - thus "splitting" the beam into two sections. Then apply the equations of equilibrium to one of the two sections. Problem 513 is easier than most solved examples found on this topic in any Strength of Materials textbook. Here's a similar problem inspired by a solved example we find in Mechanics of Materials by R.C. Hibbeler