pls answer my question

Question

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.

Answer 1

The sum of the moments of the three forces must balance if the bar is to remain stationary.

It's not clear from the question what a, b and c are. Since the bar is homogeneous the dimensions of the bar would not be significant. However, the points of application of the forces are important to determine what moments to apply. Assume that the bar operates like a seesaw with a central pivot, and that the bar's length is 1+0.4+0.6=2m. P1 is assumed to be a distance of 1m from the pivot, while P2 is 0.4m on the opposite side of the pivot and P3 0.6m. The moments must balance so P1=15*0.4+9*0.6=6+5.4=11.4, making P1=11.4KN.