Propositions of Statics: Weights, Cords and Supports
Theorems 6a-14a - a cord doubly loaded, force of infinite power, and the heavier part guiding motion
The page continues Leonardo's numbered statics with a set of theorems on weights, cords and supports. Among them: that a suspended gravity acts through the whole length of its support; that a support bears twice the weight it holds; that force has the utmost lightness yet the power of infinite weight; and that a support is pulled at its opposite ends by two equal powers. A worked case shows that where the weight is 3, the support at m sustains 6, holding both the power of 3 and its equal resistance. Balance and pulley diagrams carrying the numbers 4 and 8 illustrate the theorems.
On this page
Why a support of weight 3 sustains 6
Reasoning from the earlier theorems, the note argues that the weight f acts through every part of its support n r f, that its power equals its resistance n, and that the cord is burdened by double the weight. Hence, with a weight of 3, the support at m sustains 6, holding both the power of 3 and its equal resistance.
Force of infinite power; mobile parting from motor
The 14th proposition states that force has the utmost lightness yet the power of infinite weight. The 12th treats the mobile separating from the motor: the more powerful the motor is than its mobile, the greater the motion of that mobile compared with the motor's, given equal figure and matter.
Theorems 6a-11a on weight and support
The left column gathers further theorems: that power without motion equals its opposite resistance; that equal bodies descending in equal time are equal and move on parallel lines; that every heavy body weighs along the line of its motion; that the heavier part guides the motion; that a support suffers twice the weight it holds; and that a suspended gravity acts through the whole length of its support, which is pulled at its opposite ends by two equal powers.
