Here is a simple diving board. You can set the masses of the person on the board, and the board itself. You can move the person along the top of the board, and you can move the green pivot point (x1, x2 = the fractions of the length along the board). {Keep the distance of the pivot greater than zero to avoid infinite forces!} The weight vectors are shown for the board, and the person, and the values of those weights are shown above the location of the weight. The force vectors for the left post, and the moveable pivot are shown (with the directions shown), and the values of those forces are shown below where the forces act. 
