Engineering Statics

C-19


For the boom and loading shown, determine the tension in cord BD and the reaction at point C.

The FBD shows the 3 kip force at A, the tension and the two components of force at C.  Note that  for a cord the 
force must be along the cord.  The x and y components hence 
are proportional to the geometry.
The geometry for the cord is a 24,32,40 (3,4,5) triangle.
The moment equation is written about point B.
Force equilibrium exists in the x-direction.
Force equilibrium exists in the y-direction.
The equations are rewritten with all C<sub>x</sub> terms 
under each other, C<sub>y</sub> terms under each other and 
T terms under each other on the left side of the equation. 
Constants are on the right side of the equation. 
<p> 
The simultaneous equation solver on your calculator can solve 
for three equations in 3 unknowns.
Solutions for the three unknowns C<sub>x</sub>, C<sub>y</sub> and T 
are from the calculator.