a homogeneous prismatic bar is loaded by forces P1,P2,and P3 acting at points B,C, and D, respectively. the dimensions of the bar are as follows : a=1.0m b=0.4m, and c=0.6m . Assuming that P2=15KN and P3=9KN, determine the force P1 so that the lower end D of the bar does not move vertically when the loads are applied.