Consider the three forces acting at O and in equilibrium as shown in the figure. Which of the following equations is/are CORRECT?
I. P1 cos θ1 = p1 cos θ2
II. P3 = P1 cos θ4 + P2cos2
III. P1 sinθ1=P2 sinθ2
resolving P1, P2 and P3 into x and y component
Px = P1Cosθ1
Py = P1Sinθ1
Px = P2Cosθ2
Py = −P2Sinθ2
Px = −P3Cosθ0
therefore
total Px = P1Cosθ1 + P2Cosθ2 + −P3Cosθ0 = 0
total Py = P1Sinθ1 + −P2Sinθ2 = 0
so that P1Sinθ1 = P2Sinθ2
P3Cosθ0 = P1Cosθ1 + P2Cosθ2
