Six laws of force and motion in pulley tackle
Continuing the study of compound blocks: how weight and speed vary along the ropes.
Continuing the study begun a few pages earlier, Leonardo sets out six numbered propositions on the behaviour of compound tackle-blocks. He observes that the driving force is not uniform along the ropes but grows or lessens with nearness to the motor, that rope motion slows the farther it lies from the motor, and that the lower block does not rise evenly with its wheels. Blocks of many wheels require two opposed motors; and of the ropes, those descending feel more weight while those ascending move more slowly. The margin carries three groups of pulley diagrams driven by two motors a and b.
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Six propositions on force and motion in the ropes
The power of the weight's motor is not uniform in the ropes but grows or diminishes with proximity to the motor, and rope motion slows with distance from it. The lower block does not rise equally with its wheels; blocks of many wheels need two opposed motors; descending ropes feel more weight while ascending ropes move more slowly.
Compound blocks driven by two motors
Along the margin three groups of tackle-blocks are drawn, threaded so that their ropes run between the sheaves. The points a and b mark the positions of the two driving motors that work the system.