architecture

1. EQUILIBRIUM OF FORCE
SYSTEM
PREPARED BY:
ENGR. KENT JEYLUCK BORBON
STATICS

2. The body is said to be in equilibrium if the resultant of all
forces acting on it is zero. It means the effect of the given
force system is zero and the particle or rigid body is said to
be in equilibrium.
Formulas:
Concurrent force system
ΣFx=0
ΣFy=0

3. Problem:
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.

4. Free body diagram

5. Solution
ΣFH=0
Ccos45°=Tcos30°
C=1.2247T
ΣFV=0
Tsin30°+Csin45°=600
Tsin30°+(1.2247T)sin45°=600
1.366T=600
T=439.24 lb answer
C=1.2247(439.24)
C=537.94 lb answer

6. By Force Polygon
T = C = 600
sin45° sin60° sin75 °
T=439.23 lb (okay!)
C=537.94 lb (okay!)