Weight of a rod shared between two suspending cords
How the load shifts as one cord moves toward the rod's centre
Leonardo sets out a statics problem: a rigid rod hung by cords at each of its two ends divides its weight equally between them. He then examines what happens when one cord is held fixed and the other moves toward it or toward the rod's centre, arguing that weight is transferred from one cord to the other in proportion to the distances involved. Two horizontal rod-and-cord diagrams, annotated with numbers such as 4 4 and 2 2/3 5 1/3, illustrate the shifting distribution of the load.
On this page
Equal division of a rod's weight between its two end cords
A rod suspended by cords at each of its two ends divides its weight equally between the two cords. This is the balanced starting case, before either cord is displaced along the rod.
Weight transferred when one cord moves toward the other
If one cord stays fixed and the other moves toward it, weight leaves the fixed cord and joins the weight already carried by the movable one. The diagram is marked 4 4 - 4 4 for the balanced position.
Proportion between shifted weight and cord displacement
The more one cord moves toward the centre of the rod, the more weight it takes from the other cord. The weight that shifts between the cords bears the same proportion to the original weights as the motion made by the cord bears to the remainder of the rod. The lower diagram is marked 2 2/3 and 5 1/3 against the balanced 4 4.