Cracking the SAT Physics Subject Test

This gives us the tension in each of the ropes noted in the figure.

12. The figure below shows a homogeneous bar of mass M and
    length L, with one end attached to a hinge on a wall and the other
    end supported by a string. What’s the tension in the string?

Here’s How to Crack It

Let T be the tension in the string, let L be the length of the bar. The weight of the bar
acts at the center of mass (halfway down the bar) so the force diagram looks like
the following: