I honestly have no idea how to set it up, i just plugged it into an equation my professor showed me on a similar problem today. which is mvr=.5ml^2 +md^2
so .05*v*4=1/12 *8.6 *16^2 +.25*4^2
A solid balsa cube of side length L = 16.0” and mass M = 8.60 kg is at rest on a horizontal table top. It is constrained to rotate about a fixed and frictionless axis, AB, along one edge of the cube. A bullet of mass m = 50.0 g is fired with speed v at the other side of the cube, at height a =...