To weigh trucks and other heavy objects, the scale consisting of the horizontal bar AB of length L articulated to the ground in O is used, located at L/3 of the end A and by the piece BCEF articulated to the bar in B, where the section BE is vertical and the section CF is horizontal. If the piece is connected to the ground by means of the horizontal D cord; determine the weight Q of the truck according to the weight P of the block that guarantees the balance of the scale. The elements that make up the scale are of negligible weight.