Today we learned how to "add" vectors! Vectors can represent lots of different quantities...displacement, velocity, acceleration. But for now we are using them to represent force. The head-to-tail method means that the head of one vector is placed at the tail of another vector. If all the force vectors on an object make a closed shape, then the forces balance. Otherwise there is some amount of force "left-over". Students worked on some sample problems in class using rulers and protractors. It is really important to pay special attention to the angle measures and scale. Try some of these over the weekend if you were really confused in class.
(Image from Hyperphysics)