Forces in a cord wound on a rod, and pulley blocks

Which feels more force, the anchor a or the grip c

If the cord ba is fixed at a and wound around the rod d and pulled at b, Leonardo asks whether the attachment a or the tightening at c feels more force. He answers that c feels double a, because it feels both a and b.

A winding cord feels double the lesser end-power

A cord that with one or more turns grips the thing enclosed within it feels only double the lesser of the two powers placed at its ends. The power at c can never exceed twice the smaller weight at a or b.

Double and quadruple pulley blocks

In the quadruple pulley the weights are unequal because each wheel weighs more on the descending side of the mover than on the side that rises from the opposite part of the diameter, since the power of the wheel always lies at the opposite ends of its diameter.

Note: 'Cleomedes the philosopher'

A short pencil jotting at the top of the sheet names Cleomedes the philosopher, apparently a memorandum of a source or authority rather than part of the mechanical argument.

Dall'alto a penna. Corda avvolta a un'asta, colle lettere:

La nota continua a sinistra sopra un disegno analogo al precedente e di fianco a un disegno mutilato con:

Sopra un'altra figura analoga alle precedenti:

A destra, figura biffata colle lettere:

Figure biffate di pesi applicati a bilance plurime, l'ultima con: 11113

In basso dalla destra, doppia carrucola con:

Quadruplice carrucola con:

In alto, a matita:

From the top, in pen. Cord wound on a rod, with the letters:

The note continues on the left above a similar drawing and beside a mutilated drawing with:

Above another figure similar to the preceding:

On the right, a crossed-out figure with the letters:

Crossed-out figures of weights applied to multiple balances, the last with: 11113

At the bottom on the right, a double pulley with:

Quadruple pulley with:

At the top, in pencil:

Forces in a cord wound on a rod, and pulley blocks

On this page

Which feels more force, the anchor a or the grip c

A winding cord feels double the lesser end-power

Double and quadruple pulley blocks

Note: 'Cleomedes the philosopher'