THE THREE LAWS OF MOTION BY ISAAC NEWTON
NEWTON’S FIRST LAW OF MOTION: INERTIA
2 Kinds of Inertia
Inertia on Rest- an object will remain at rest, unless there is force applied to move Inertia on Motion- a moving object will continue to move unless there is force applied to stop Projectiles persevere in their motions, so far as they are not retarded by the resistance of the air, or impelled downwards by the force of gravity. A top, whose parts by their cohesion are perpetually drawn aside from rectilinear motions, does not cease its rotation, otherwise than as it is retarded by the air. The greater bodies of the Planets and Comets, meeting with less resistance in more free spaces, preserve their motions both progressive and circular for a much longer time.
NEWTON’S SECOND LAW OF MOTION: ACCELERATION
Newton’s second law is often stated as F=ma which means the force (f) acting on an object is equal to the mass (m) of an object times its acceleration (a). This means the more the mass an object has more force you need to accelerate and greater force the greater the acceleration. If any force generates a motion, a double force will generate double the motion, a triple force triple the motion, whether that force be impressed altogether and at once, or gradually and successively. And this motion (being always directed the same way with the generating force) if the body moved before, is added to or subducted from the former motion, according as they directly conspire with or are directly contrary to each other; or obliquely joined, when they are oblique, so as to produce a new motion compounded from the determination of both. *2 forces acting on an object are equal there is no motion the object is at rest *2 forces acting on an object are not equal (unbalanced) there is motion it will follow the direction of the greater force *more force applied the grater the acceleration
*the lesser the mass the greater the acceleration
NEWTON’S THIRD LAW OF MOTION: ACTION REACTION
Whatever draws or presses another is as much drawn or pressed by that other. If you press a stone with your finger, the finger is also pressed by the stone. If a horse draws a stone tyed to a rope, the horse (if I may so say) will be equally drawn back towards the stone: For the distended rope, by the same endeavour to relax or unbend it self, will draw the horse as much towards the stone, as it does the stone towards the horse, and will obstruct the progress of the one as much as it advances that of the other. If a body impinges upon another, and by its force change the motion of the other; that body also (because of the equality of the mutual pressure) will undergo an equal change, in its own motion, towards the contrary part. The changes made by these actions are equal, not in the velocities, but in the motions of bodies; that is to say, if the bodies are not hindered by any other impediments. For because the motions are equally changed, the changes of the velocities made towards contrary parts, are reciprocally proportional to the bodies. This Law takes place also in Attractions, as will be proved in the next Scholium.
A body by two forces conjoined will describe the diagonal of a parallelogram, in the same time that it would describe the sides, by those forces apart. If a body in a given time, by the force M impressed apart in the place A, should with an uniform motion be carried from A to B; and by the force N impressed apart in the same place, should be carried from A to C: complete the parallelogram A B C D, and by both forces acting together, it will in the same time be carried in the diagonal from A to D. For since the force N acts in the direction of the line A C, parallel to B D, and this force (by the second law) will not at all alter the velocity generated by the other force M, by which the body is carried towards the line B D. The body therefore will arrive at the line...
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