Notebook on Mechanics and Natural Philosophy

Equality original: "equalita’"; in this context, it refers to a state of balance or the application of a force equal to the load. will move beyond any opposing part; so that if it possessed its own resistance The internal or external force acting against the movement. within itself, the motion would be as fast as the weight of the mover The active force or weight causing the movement. is relative to the resistance of the object that resists.

A circular diagram featuring a horizontal diameter line. Along the line are labels for points designated by the letters 's', 'n', 'f', 'r', 'm', and 'A'. Small vertical strokes above the line suggest measurements of force or distance relative to a central balance point.

If the weight is as 1 and the force is as 1, the motion is as 1.
If the force is 2 and the weight is 1, the motion is as 2.
If the force is 1 and the weight is 1/2, the motion is 1, or rather 2. Leonardo is calculating ratios; reducing the weight by half is equivalent to doubling the force.
If the weight is as 1 and the force is as 1/2, the motion will be The manuscript leaves this unfinished; following his logic, the answer would be 1/2.

The time occupied in the motion of every weight will be proportionately less for one than the other.

The force that pulls through the air in the same amount of time will be as much faster than that which pulls through the water as the weight of the air is less than that of the water.
The space occupied will be greater for one than the other in the same proportion as one weight is less than the other.

A mechanical drawing of a pulley or belt-drive system. Two wheels are connected by a horizontal cord; the wheel on the right is larger than the one on the left. Two oval weights are suspended vertically from the outer edges of the cord on both sides. The centers of the wheels are marked with points and radial construction lines.