Question

This is a depiction of 2 forces acting on a puck (top view). Which direction would a 3rd force have to be to balance the forces?

Answer 1

You can add perpendicular vectors like the sides of a right angle triangle. Just make sure they follow on from another (the "pointing" end of one vector touches the beginning of the other vector). The hypotenuse is the resultant vector.

To balance the resultant force, you need an equal but opposite force