Problem 316
Determine the values of α and θ so that the forces shown in Fig. P-316 will be in equilibrium.
 

Problem 315
The 300-lb force and the 400-lb force shown in Fig. P-315 are to be held in equilibrium by a third force F acting at an unknown angle θ with the horizontal. Determine the values of F and θ.
 

Problem 314
The five forces shown in Fig. P-314 are in equilibrium. Compute the values of P and F.
 

Problem 313
Figure P-313 represents the concurrent force system acting at a joint of a bridge truss. Determine the value of P and E to maintain equilibrium of the forces.
 

Problem 312
Determine the magnitude of P and F necessary to keep the concurrent force system in Fig. P-312 in equilibrium.
 

Problem 310
A 300-lb box is held at rest on a smooth plane by a force P inclined at an angle θ with the plane as shown in Fig. P-310. If θ = 45°, determine the value of P and the normal pressure N exerted by the plane.
 

Problem 309
A cylinder weighing 400 lb is held against a smooth incline by means of the weightless rod AB in Fig. P-309. Determine the forces P and N exerted on the cylinder by the rod and the incline.
 

Problem 308
The cable and boom shown in Fig. P-308 support a load of 600 lb. Determine the tensile force T in the cable and the compressive for C in the boom.
 

In static, a body is said to be in equilibrium when the force system acting upon it has a zero resultant.
 

Conditions of Static Equilibrium of Concurrent Forces

The sum of all forces in the x-direction or horizontal is zero.

The sum of all forces in the y-direction or vertical is zero.

Important Points for Equilibrium Forces

Problem 271
The three forces in Fig. P-270 create a vertical resultant acting through point A. If T is known to be 361 lb, compute the values of F and P.