1. The problem statement, all variables and given/known data Three cables are used to tie the balloon shown in the figure. Determine the vertical component of the force P exerted over the balloon at point A, if the tension on cable AB is 259 N. http://img521.imageshack.us/img521/9687/physicsballoonproblem.png [Broken] (Sorry for the figure. I had to re-draw it myself, on paint, with a touch pad. Assume all measurements are parallel to the axises, of course) 2. Relevant equations Pythagorean theorem. 3. The attempt at a solution Figured out the resulting distance of AB with Pythagorean theorem and then used cross multiplying to find out the equivalent vertical component of AB. Then... What I did: Simply multiplied that resulting vertical force (207.2 N) times three for each of the cables, for a vertical resultant of 621.6 N. What the teacher did: He also found the x component of AB and equaled it to the x component of CA, found the z component and equaled it to that of AD. Then, with lots of triangle solving, found the three different y components and added them all up for a result of 1000-something N. MY QUESTION: How would you go about solving this problem? The teacher reasoned that the x and z components had to be in equilibrium to find the y resultant. I disagree because he never stated that the balloon was in equilibrium anywhere. Is he wrong? Or should I always assume that, when finding a component, all other components should be balanced? This is a test question and he's very stubborn so I want to know what you all think.