1. The problem statement, all variables and given/known data I'm trying to find the boundary conditions for the beam shown in the figure. 2. Relevant equations Notation: V= Shear force M= Bending moment 3. The attempt at a solution at x=0 V=R1, M=0 at x=9 V=R3, M=0 In the solution provided at x=9 V=-R2. I don't understand why it's negative, since I took upwards as positive. Help appreciated!