Leonardo in these notebooks attempts to standardize physics, or the learning of mechanics, with laws of motion, reaction, and time. Leonardo simplifies mechanics discussing the actions of screws, hammers, and wheels.
Leonardo da Vinci states what remind me of Newton’s fundamental laws we have all learned in general physics. Except with a different objective. Whereas Newton proclaimed three revolutionary principles in which all of physics applied, Leonardo focuses on the thoughts of everything being halved. “If a power move a body in a certain time a certain distance, half the force will move in the same time half the body half the distance.” It appears here that da Vinci wasn’t trained in the language of mathematics, for what the genius is explaining here is absolutely mindless common sense derivation of power. Multiplying by two or halving one side of the equation will in result, halve the other side of the equation.
Leonardo initially intrigued me with his definition of impetus. It reminded me first of a battery. “Impetus is a power created by movement and transmitted from the mover to the movable thing; and this movable thing has as much movement as the impetus has life.” I brought into mind the energy of a battery, powering a portable cd player, for as long as the battery has life. Leonardo speaks of power created by movement. Windmills, and watermills come into view, as well as electromagnetic power, where movement between two poles, encapsulated, yields power. Impetus is later described as a derived movement, or a secondary reactionary movement. Impetus is the gradual slowing of an action; Leonardo uses a bow-and-arrow as an example.
Leonardo explicitly uses Newtonian thought in his explanation of impetus: “…the object which it strikes first, as in the blow given to the sculptor’s chisel which is afterwards transferred to the marble that he is carving.” Newton so declared for every action there is an equal and opposite reaction. Leonardo in his correlation of energy loss and transfer by way of a sculptor’s chisel derives the blow or force acted on the chisel is transferred or reacted by the marble.
Leonardo explains the delay between action and the inevitable reaction of a system. “Why it is first the blow rather than the movement caused by it; the blow has performed its function before the object has started on its course.” Leonardo is catching the detail of action-reaction with this comment. The moment before a force acts upon an object, and the moment after the force acts upon an object; two extremely different situations, and two totally different systems of forces. “The blow is born by the death of motion, and motion is born by the death of force.” This conclusion puzzled me. What does he mean by “death of motion?” Is he describing a vibrating mechanism, or a perpetual hammer, whereas the instances which Leonardo is studying, the moment the force stops and starts, and the moment motion commences and halts. Leonardo continues, “Force is caused by motion injected into the weight,” which is incorrect in my opinion. A force not necessarily causes motion, an example given by our weight or the effect of gravity.
Leonardo created a guideline or statute for studying mechanics. First, begin with motion by weight, then impetus (whatever it is), and rotation, then wheels, screws, teeth, then a final course incorporating all the bases: “Wheels and batten with rope and with teeth.”
Friction was of study by the great one. He divides friction and its application into three categories. Irregular friction and Leonardo’s basis for it infers me to believe that mathematics was a cause for this “irregular” title. As I read the definition of irregular friction, “…made by the wedge of different sides,” implies a face of a wedge at different angles, and the components derived from such angles. The first two categories of friction, simple and complex, are on the ground (level) or between two objects, perpendicular to the ground, and with that of gravity. The angled wedges, and their components, with gravity and along the ground, were of need of mathematics to obtain. Leonardo creating their own category for friction along surfaces not along or normal to the level ground, invokes the thought that Leonardo’s lack of formal mathematics hindered his study of mathematics, as identified to me in these notebooks.