HYDRAULIC ARCHITECTURE. BOOK I.

2. One calls the direction or determination of a Power, the straight line along which this Power pushes or pulls a body.

3. One calls the effort, impression, or moment In this context, "moment" refers to the effectiveness or the turning effect of a force, rather than a moment in time. of a Power, that which the manner in which it is applied to a body or a machine allows it to act against the obstacle to be overcome.

4. When it is said hereafter that a body is moved on a horizontal plane by one or several Powers, we will assume, for the sake of better understanding, that the force of each Power is attributed to a hand that pushes this body along a straight line with a force that is always uniform original: "uniforme"; meaning a constant force that does not speed up or slow down. to make it cover equal spaces in equal times; that is to say, if this Power, while pushing the body successively, made it cover a space of 6 feet in 6 seconds of time, it would make it cover one foot for every second.

Since it is not necessary for a Power to be applied immediately meaning "directly" or "without mediation" to a body to push it, one may assume, if one wishes, that it makes use of a solid rod original: "rayon solide"; here referring to a rigid mechanical connection like a pole or beam, as one does with a billiard cue when one wishes to push a ball with a uniform force along the same Direction. Since the force that the hand pushing a ball might possess is far from being totally employed in moving it, one should take care that when we say a body is pushed or pulled by one or several Powers, one must understand by these Powers only the force that each exerts to pull or push that body, and not all the force that it might potentially have.

5. When several Powers push or pull a body, their Directions must be considered as being contained within the same plane; and when they are applied to ropes, we will set aside the stiffness and the weight of these ropes This is a common "idealization" in classical mechanics, allowing the student to calculate forces without the complicating variables of real-world materials..

6. Whether one or several Powers push or pull a body, the Directions along which they act will always be marked by those of the solid Rods or the ropes to which these Powers are applied; and one may regard their effort as extending equally through all points of their directions, without worrying about the distance at which these Powers are located from the body upon which they act; the greater or lesser length of the ropes or rods cannot cause any alteration to their effect.

7. One can also receive as incontestable that action is equal to reaction; indeed, the action of a force against a body can only be equal to that which the body has to push back against it.

Direction / Determination: the path along which a force is applied. Power: the active force (source of motion). Moment: the specific action or "punch" a force delivers based on how it is applied. Uniform Force: a force that produces constant speed. Solid Rod: a rigid connector used to transmit force from a distance. Action and Reaction: the principle that every force exerted is met by an equal force in the opposite direction.