This lab uses an object in equilibrium with several known forces acting on it as a means to demonstrate that the force vectors can be added up to give zero. Students are to set up the force table and then draw a vector diagram of the forces acting on the central ring to show that the vectors add to zero. A common problem students have is determining an appropriate scale factor for expressing a given force by a vector of a given length. They should chose something that is small enough for them to fit their vector diagram on a single sheet of paper, but large enough to fill most of the sheet.
As always please remind students to keep track of uncertainty in their measurements and to report their results in a well written lab report.