the beam below has a pin support at A and a roller support at B$.$ Ignore the weight of the beam, a$)$Draw the free body diagram for the beam b$)$ determine the reaction of supports at A and B$.$ A $400$lb$/$ft $900$lb $3$ft$.$ Develop shear and bending moment diagrams and determine fuctions for shear and moment using the method of sections for teh region defined by $0<$ x $<6$