Hanging from the front office of a dental office is a sign that weighs 120N and is suspended at the end of a .8 meter long support beam that weighs 10N. What is the tension in a supporting wire that holds the sign at an angle of 20 degrees?

Answer 1

I don't know in which direction the support beam is, I assume horizontal.

You have two things establishing equilibrium: sum of forces in any direction is zero, and sum of moments about any point is zero.

There is not much I can do here to work it, labeling the diagram is critical before writing the equations.

See prob 8:17 http://hep.physics.wayne.edu/~harr/courses/2130/f99/lecture13.htm