then (I) if is a right angle, the body at A will as a result of the two forces describe the complete diagonal of the parallelogram in the same time that it would have described one of the sides or if moved by only one of the two forces; if is acute, the body will describe only part of the diagonal, even if it were elastic as is supposed of all three bodies; if the angle is obtuse, the body will go well beyond the diagonal, and the farther beyond it as the angle is more obtuse, in the same time that it would have described the sides.