Collision

“ When we neglect the nature of this deflection we are considering the forces involved, but if we consider results and compare the paths of the bodies before collision with the paths after collision, we pass from the consideration of force to causation, for the cause of their collision was their incident paths and the effect of collision their reflected paths. ”

“ All these inquiries are superfluous where the collision was caused by a vessel having the power to move or stop at pleasure in a channel of sufficient breadth, without any superior force compelling her to the place of collision. ”

“ The consequences of such a collision are easy to foretell, provided that we know the masses and the velocities of the colliding bodies. In a preceding chapter we have discussed the motions of the sun and stars, and have seen that they are so swift that an encounter between any two of them could not but be disastrous. ”

“ Inability to avoid a collision usually exists at the time the collision occurs; but it is seldom a matter of much difficulty to trace the cause of the disaster to some antecedent omission of duty on the part of one or the other, or both, of the colliding vessels. ”

“ The following table is almost universally now adopted as showing the traction upon level roads formed of different materials, asphalte being taken as the standard of excellence in this respect.
[29]
There are four forces constantly at work tending to destroy the momentum of vehicles passing along a roadway: they are gravity, collision, friction, and the resistance of the air. ”

“ Under those circumstances, it is correct to say that inevitable accident, as applied to such a case, must be understood to mean a collision which occurs when both parties have endeavored by every means in their power, with due care and caution, and a proper display of nautical skill, to prevent the occurrence of the accident. When applied to a collision, occasioned by the darkness of the night, perhaps a more general definition is allowable. ”

“ By preventing such encroachments, it prevents collision and conflict between them. These are their natural offspring: collision follows encroachment — and conflict, collision, in the order of events — unless encroachment be acquiesced in. ”

“ Again, the mechanical actions which produce heat—friction, and the collision of bodies—must from the nature of the case produce a shock, that is, an internal motion of particles, which indeed, we find, is often so violent as to break them permanently asunder. ”

“ If the collision does not destroy them, they may either break apart at the point of the collision, and then weld together into a single ring with twice the diameter, and then move on as if a single ring had been formed, or they may simply bounce away from each other, in which case they always rebound in a plane at right angles to the plane of collision. ”

“ On collision the bodies will evidently come gradually to rest, and then under the action of the elastic forces developed start up and move back on their original paths with the respective velocities -u and +u of the same magnitude as before. ”

“ Thus collisions which might result simply in deflection if the particles acted severally, produce fracture when they act conjointly. Particles may produce pressure when they act separately, but when they act conjointly pressures may lead to rupture. By the device of the lever forces are multiplied in effect without increase or diminution of force as such ”

“ See collisions and wrecks and every mode of disaster by land and by sea, resulting chiefly from the insanity for speed, in those who for the most part have nothing to do at the end of the race, which they run as if they were so many Mercuries speeding with messages from Jupiter. ”

“ All at once from the dark line of the horizon whither it retired to gain its momentum, the monster rushed suddenly towards the Abraham Lincoln with alarming rapidity, stopped suddenly about twenty feet from the hull, and died out—not diving under the water, for its brilliancy did not abate—but suddenly, and as if the source of this brilliant emanation was exhausted. Then it reappeared on the other side of the vessel, as if it had turned and slid under the hull. Any moment a collision might have occurred which would have been fatal to us. ”

“ Supposing, now, the particles within the orbit of the planet to be equally distributed according to their major axes, then as the velocity of any one of them, taking approx. as unity, is
,
the mean velocity of all of those which may encounter the satellite is, at the point of collision,
that is, just over three-quarters of the planet's speed in its orbit. ”

“ My first thought was that a man who had come through a collision and rubbed shoulders with death merited more attention than I received. ”

“ Rear-end collisions occur most frequently, although head-to-head collisions annually claim many victims. When an accident of this kind is impending, the engineer generally has but a few seconds of warning ”

“ The coldest bodies warm with opposition, the hardest sparkle in collision. ”

“ So the laws of good driving forbade you to go off the magic ribbon except in extreme emergencies. You were ethically entitled to several inches of margin at the right-hand edge; and the man approaching you was entitled to an equal number of inches; which left a remainder of inches between the two projectiles as they shot by. It sounds risky as one tells it, but the heavens are run on the basis of similar calculations, and while collisions do happen, they leave time enough in between for universes to be formed, and successful careers conducted by men of affairs. ”

“ Now it has been shown mathematically in several different ways that when small particles collect into a larger mass, the collisions tend to make the resultant orbit of the combination both more circular and more conformant to the general plane than its constituents. But we may see this more forthrightly by means of the general principle enunciated above. For in fact both results are direct outcomes of the conservation of moment of momentum. Given a certain moment of momentum for the system, the total energy of the bodies is least when they all move in one plane. ”

“ High in the air shot a shower of sparks, and every now and then a wall would fall in with a crash that sounded loud above the puffing of the engines, the shrill tootings of the whistles, and the hoarse cries of the firemen. ”

“ When, as yesterday, every sixteen minutes a tremendous jarring crash tells you that a shell has fallen somewhere in the city,—and the concussion is so great that it always sounds as if it had fallen in the next block!—you see people turn their heads as they walk, staring in the direction of the explosion ”

“ Any one of our readers who has ever seen a train of luggage wagons being shunted is familiar with the way in which the shock of a sudden pull or push on the part of the engine travels all down the line of wagons, and we may think of the shock of an earthquake as travelling along and through the earth in the same way. Observation, however, shows that these waves are propagated farthest in one particular direction. ”

“ The force of the explosion may be imagined when it is recollected that they had to give the car a velocity of more than seven miles per second in order to overcome the attraction of the earth and the resistance of the atmosphere. ”

“ The violence of the upward motion of the ground was singularly illustrated by the inversion of heavy bodies lying on the surface, and which can hardly be accounted for, except on the supposition that they were actually thrown to a considerable distance into the air. ”

“ For some days, it wandered first on the surface, and then beneath it, amid those fogs so dreaded by sailors. What accidents are due to these thick fogs! What shocks upon these reefs when the wind drowns the breaking of the waves! What collisions between vessels, in spite of their warning lights, whistles, and alarm bells! And the bottoms of these seas look like a field of battle, where still lie all the conquered of the ocean; some old and already encrusted, others fresh and reflecting from their iron bands and copper plates the brilliancy of our lantern. ”

“ The other observation is, that the arrows of fortune, as well as all others, derive their force from the velocity with which they are discharged; for, when they approach you by slow and perceptible degrees, they have but very little power to do you mischief. ”

“ The proportion between the velocity with which men or animals move, and the weights they carry, is a matter of considerable importance, particularly in military affairs. ”

“ Windmills, which are used in the great plains of Holland and North Germany to supply the want of falling water, afford another instance of the action of velocity. The sails are driven by air in motion—by wind. ”

“ But not only must we seek the measure of motions and actions by themselves, but much more in comparison; for this is of excellent use and very general application. Now we find that the flash of a gun is seen sooner than its report is heard; [p. 212] although the ball must necessarily strike the air before the flame behind it can get out; and this is owing it seems to the motion of light being more rapid than that of sound. We find too that visible images are received by the sight faster than they are dismissed; ”

“ A wheel, if frictionless like a molecule, could revolve on its bearings forever; if it were small enough, its motion would forever escape observation. Were it dropped from its bearings, through however short a distance, to a horizontal plane, part of its energy would be at once expressed in its advancing in a line long enough for detection. The question behind attraction and repulsion is, How shall two distant bodies move on their axes, or in their orbits, so as to act on a chain of intervening bodies with the effect that the two shall approach or recede from each other? ”

“ I remember I felt an extraordinary persuasion that I was being played with, that presently, when I was upon the very verge of safety, this mysterious death—as swift as the passage of light—would leap after me from the pit about the cylinder, and strike me down. ”

“ Then speeds are associated with speeds, motions with motions, forces with forces, energies with energies, powers with powers, coöperations with coöperations, and all of these modes of motion are interrelated or associated and all are considered in dynamics. ”

“ The great weight of the ship may indeed prevent her from acquiring her greatest velocity; but when she has attained it, she will advance by her own intrinsic motion, without gaining any new degree of velocity, or lessening what she has acquired. ”

“ But why drives on that ship so fast, Without or wave or wind? SECOND VOICE. The air is cut away before, And closes from behind. ”

“ And in the air are no streets, no channels, no point where one can say of an antagonist, "If he wants to reach my capital he must come by here." In the air all directions lead everywhere. ”

“ In the height of the gusts, in my high position, where the seas did not break, I found myself compelled to cling tightly to the rail to escape being blown away. My face was stung to severe pain by the high-driving spindrift, and I had a feeling that the wind was blowing the cobwebs out of my sleep-starved brain. ”

“ Now, the velocity of wave propagation can be seen, without the aid of any mathematical analysis, to depend on the elasticity of the medium and its density; for we can see that if a medium is highly elastic the disturbance would be propagated at a great speed. ”

“ If a body impinge 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. ”

“ Country in which there are precipitous cliffs with torrents running between, deep natural hollows, confined places, tangled thickets, quagmires and crevasses, should be left with all possible speed and not approached.
16. While we keep away from such places, we should get the enemy to approach them; while we face them, we should let the enemy have them on his rear. ”

“ As my driver prophesied when I was ploughing, they warmed me twice, once while I was splitting them, and again when they were on the fire, so that no fuel could give out more heat. ”

“ Bursts as a wave that from the cloud impends, And, swell’d with tempests, on the ship descends; White are the decks with foam; the winds aloud Howl o’er the masts, and sing through every shroud: Pale, trembling, tired, the sailors freeze with fears; And instant death on every wave appears. ”

“ In our gliding experiments we had had a number of experiences in which we had landed upon one wing, but the crushing of the wing had absorbed the shock, so that we were not uneasy about the motor in case of a landing of that kind. ”

“ The earthquake, however, must be to every one a most impressive event: the earth, considered from our earliest childhood as the type of solidity, has oscillated like a thin crust beneath our feet; and in seeing the laboured works of man in a moment overthrown, we feel the insignificance of his boasted power. ”

“ At half-past two o’clock of a moonlit morning in March, I was awakened by a tremendous earthquake, and though I had never before enjoyed a storm of this sort, the strange thrilling motion could not be mistaken, and I ran out of my cabin, both glad and frightened, shouting, “A noble earthquake! A noble earthquake!” feeling sure I was going to learn something. ”

“ The moral effect of the thundering of one's own artillery is most extraordinary, and many of us thought that we had never heard any more welcome sound than the deep roaring and crashing that started in at our rear. ”

“ In battle, there are not more than two methods of attack—the direct and the indirect; yet these two in combination give rise to an endless series of maneuvers. ”