Any group of 2 or more forces is balanced if the sum of all of their strengths and directions adds up to zero. Here's an example that I just made up:. Take 50 ropes. Tie one end of every rope all together into one big fat knot, and then have a tug of war in 50 different directions. Get 10 football players and 40 cheerleaders to each take the end of one rope, then everybody spread out and start pulling. It's possible that if everybody stood in just the right place, they might all cancel each other out, and the big knot in the center might just hang there and not move at all ... just as if there was NO FORCE on it at all. If that happened, we would know that the group of 50 forces acting on the knot is "balanced".
