Engineering Statics

A-11


The end of the television cable, AE is attached to pole AB, which is supported by cables AC and AD. Knowing that the tension in cable AC is 140 pounds, determine the components of the force exerted by this cable on the pole.

We draw a free body diagram of point A examining only cable AC.
ACxz is vector AC projected onto the x-z plane.
AC is 140 pounds at a 60° angle with the x-z plane.
Knowing ACxz, we then project the result onto the x-axis.
Similarly, we project ACxz onto the y-axis.
Notice that the component is negative.
Finally, we projec ACxz onto the z-axis.
Notice that that component is also negative.