Determine the concurrent forces:
Four coplanar concurrent forces act at point and keep it at rest. These are mention in Figure. Determine the forces P and Q.
Let us assume that forces P and Q act away from the point O. As the point O remains at rest, we may apply equations of equilibrium
∑ Fx = 0
∴ 310 + P cos 60o - 1260 cos 60o = 0
∴ 310 + 0.5 P - 1260 × 0.5 = 0
∴ P = (630 - 310) /0.5 = 640 N
As P works out to be positive, its assumed direction is correct. Thus, P acts away from O.
Also, ∑ Fy = 0
∴ P sin 60o + 1260 sin 60o - Q = 0
∴ Q = (640 + 1260) sin 60o
∴ Q = 1645.4 N
As Q is also positive, the assumed direction of Q is correct. Therefore, Q acts away from O.