Engineering Statics

A-12


A transmission tower is held by three guy wires anchored by bolts at points B, C, and D. If the tension in wire AB is 525 pounds, determine the components of the force exerted by the wire at point C.

We draw a free body diagram of the force at point B.
We calculate the length of the cable, BA.
The force is proportional to the geometry of the wire.  Since the hypotenuse is 105.16, the x component is 22/105.16 of the tension of 525 pounds.
Similarly the y component is 100/105.16 of the 525 pound force.  Since the y component is up, it is 499.24 pounds.
Finally, the z component is -24/105.16 of the 525 pound force.  Since the z component is back (in the negative z-direction), it is -119.81 pounds.