VENI VIDI DA VINCI

Collections Newsletter Guild About Developers Patron Sign In

Library/Codex Forster II/087r

Prev175 / 324Next

Codex Forster II — 087r

100%

Reset zoom

© Victoria and Albert Museum, London

Chi sa quanto peso leva le 100 libbre allo 'nsu per quest'obliquità, sa la fatica della vite.

Peso trascinato su piano inclinato, con:

100

A volere la vera notizia della quantità del peso che debbe movere le 100 libbre sopra la strada obliqua, bisogna sapere la natura del contatto che esso peso ha col piano dove si confrega per lo suo moto, perché vari corpi hanno varie confregazioni. Con ciò sia che se saranno due cor[p]i di varie superfizie, cioè che l'una sia delicata e pulita e bene unta o insaponata, e sia mossa sopra un piano di simile natura, essa sarà molto più facile al movimento che quella che sarà ruvida a uso di lima o di raspa; sì che sempre, quando voi sapere la quantità della forza che debbe per diverse obliquità di strade stracinare un medesimo peso, ...1

Whoever knows how much weight raises the 100 pounds upward along this incline knows the effort of the screw.

Weight dragged up an inclined plane, with:

100. To have true knowledge of the amount of weight that must move the 100 pounds up the oblique road, one must know the nature of the contact that this weight has with the plane on which it rubs in its motion, because various bodies have various frictions. For if there were two bodies of different surfaces — that is, one delicate and polished and well oiled or soaped, moved over a plane of like nature — it would be much easier to move than one that is rough after the manner of a file or a rasp; so that always, when you wish to know the amount of the force that must, over different obliquities of roads, drag one and the same weight, …

Raising 100 lb up an incline; the labour of the screw

A ramp with pulley and a 100-lb box, and how surface friction governs the pull.

Physics & Mechanics Machines & Devices

A pulley mounted at the top of a ramp lifts a hanging weight while a box marked 100 rests on the inclined plane. Leonardo states that whoever knows how much weight is needed to raise the 100-lb load up this slope thereby knows the effort demanded by the screw. He then argues that the true force required depends on the friction between load and surface, since smooth, oiled or soaped bodies slide far more easily than those rough as a file or rasp. The paragraph breaks off and continues on the following page.

On this page

The pull that raises 100 lb up the incline

Leonardo asserts that whoever knows how much weight raises the 100-lb load upward along this slope thereby knows the effort demanded by the screw. The drawn ramp, its pulley, and the box marked 100 embody the problem of the inclined plane.

Friction depends on the nature of the contact

To find the true force needed to drive the 100-lb load up the slope, one must know the nature of the contact where it rubs, since different bodies rub differently. A fine, polished, well-oiled or soaped surface moves far more easily than one rough as a file or a rasp.

Reader's Edition — described with AI from the e-Leo transcription.