Speed

“ COÖPERATION
We have already discovered the nature of motion in its absolute as speed and its relative as path. The speed of the ultimate particle has never been measured; but bodies as such have their specific speeds and one is greater than another. Speed of a body is the rate at which it changes its position, regardless of the change of position of its particles to one another. ”

“ If I pass along a street at some unheard-of speed, but with a uniform motion, its general aspect may, on account of the contraction caused by my velocity, be a little different from what it would seem to me if I were stationary. ”

“ My dear boy, who knows what the human body can stand? When the locomotive was first invented learned scientists predicted that the limit of speed was thirty miles an hour, as the human body could not stand a higher speed. To-day the human body stands a speed of three hundred and sixty miles an hour without ill effects. At any rate, on my first trip I intend to take no chances. We know that the body can stand an acceleration of thirty-two feet per second without trouble. That is the rate of acceleration due to gravity and is the rate at which a body increases speed when it falls. ”

“ The speed of a body which has in this manner acquired any momentum whatever will, when converted into uniform motion, retain precisely such a speed as, during a time-interval equal to that of the fall, will carry the body through a distance equal to twice that of the fall. ”

“ Only in one case was I at all satisfied of being able to count the rate of speed by a stop-watch, and, if I am not mistaken, there were thirty in ten seconds; generally one's eye can no more follow the legs than it can the spokes of a carriage-wheel in rapid motion. If we take the above number, and twelve feet stride as the average pace, we have a speed of twenty-six miles an hour. ”

“ Sit down some day when you have nothing else to do and discover the principle of infinite speed. I mean the law of motion which shall accomplish an infinitely great distance in an infinitely short time. You may mix in a little practical mechanics, if you choose. Invent some method of taking the tardy courier over his road at the rate of sixty miles a minute. Demonstrate me this discovery (when you have made it!) mathematically, and approximate it practically, and Abscissa is yours. ”

“ We jog along at a respectable rate, not too fast and not too slow, say forty-five miles an hour top speed, and twenty-five mean, which allows us to see things to-day and remember what we saw yesterday. ”

“ We determine the velocity of a railway train by the time it takes to pass from one mile-post to the next. We learn the speed [Pg 263] of a rifle bullet by an ingenious contrivance really founded on the same principle. The greater the velocity, the more desirable is it that the distance traversed during the experiment shall be as large as possible. In dealing with the measurement of the velocity of light, we therefore choose for our measured distance the greatest length that may be convenient. ”

“ And thus, it seems, we shall not be far wrong if we put the increment of speed as proportional to the increment of time; hence the definition of motion which we are about to discuss may be stated as follows: A motion is said to be uniformly accelerated, when starting from rest, it acquires, during equal time-intervals, equal increments of speed. ”

“ ABOUT SPEED Speed is so important in the development of good writing that it should receive close attention in all practice work until correct speed has become a habit. Too much speed is just as bad as too little. Correct speed forces a light, firm line; too little speed results in shaky tremulous lines; while excessive speed means irregular letter formation. If you develop a light, firm, elastic motion, and the proper degree of speed in straight line and oval making, you will find the work of the following lessons comparatively easy. ”

“ To put the matter more clearly, if a body were to continue its motion with the same speed which it had acquired during the first time-interval and were to retain this same uniform speed, then its motion would be twice as slow as that which it would have if its velocity had been acquired during two time-intervals. ”

“ He paused a moment impressively. "No one has hitherto discovered any system which will accurately record the speed of a vehicle or of any rotary movement and register it at the lowest as at the highest speeds." ”

“ Let us consider the speed and momentum acquired by a body falling through the height, say, of a spear [picca] as a standard which we may use in the measurement of other speeds and momenta as occasion demands; assume for instance that the time of such a fall is four seconds [minuti secondi d’ora] ; now in order to measure the speed acquired from a fall through any other height, whether greater or less, one must not conclude that these speeds bear to one another the same ratio as the heights of fall ”

“ But as the velocity increases uniformly with the time, we shall obtain the average speed, by finding that which the body had in the middle of the interval which elapsed between the beginning and end of the fall, and thus the space through which the body has actually fallen is that through which it would move in the same time with this average velocity uniformly continued. ”

“ When a railway train has just begun to move, its velocity v is small; but it is rapidly gaining speed–it is being hurried up, or accelerated, by the effort of the engine. So its is large. When it has got up its top speed it is no longer being accelerated, so that then has fallen to zero. ”

“ Now, it may be that there is a suite of tasks lurking in potentia that demand all this resource and more—maybe I’m like some locomotive engineer declaring that 60 miles per hour is the pinnacle of machine velocity, that speed is cracked. ”

“ Let him first fix his mind on the fact that the earth moves through space at a speed of more than sixty-six thousand miles an hour. This is a speed eleven hundred times greater than that of the most rapid express trains. ”

“ At higher speeds of rotation some light would reappear, and at lower speeds it would also reappear; by noticing, therefore, the precise speed at which there was constant eclipse the velocity of light could be determined. ”

“ Speed is the essential of motion, but the same particle in motion traverses a path. Motion, therefore, is speed and path, and can be measured in terms of space. Speed and path constitute motion.
The essential of time is persistence, but the relation of time is change; change may be measured in terms of motion. ”

“ From what has been explained, respecting the resistance of fluids, and from the relation which I have shown to subsist between the speed of horses and the performances which they are able to effect, it will be apparent that that rate of motion which renders the resistance of a fluid least injurious to the effect produced, is also that speed at which a horse can work with the greatest possible effect. This speed is from two and a half to three miles an hour ”

“ We have seen if a body is propelled forwards, and then the force acting on it ceases, that it proceeds on with uniform unchanging velocity, and if nothing impeded it, or influenced it, it would go on in a straight line at a uniform speed. ”

“ Speed depended so much on circumstances independent of the design of the vessel, such as the state of the wind and sea, that it was impossible to include a definite speed over a voyage or measured distance as one of the essential requirements of a design ”

“ From a state of rest at the beginning of the fall, the speed gradually increases with the time, and the final velocity is greater still than that which the body had at any preceding instant during its descent. ”

“ The average speed of our antediluvian express is from five to seven miles an hour, but it is perfectly satisfactory to these deliberate people; and as to ourselves, we are enjoying everything too much to wish it shortened by one minute. ”

“ Assuming that the body moved in a straight line with a speed of seven miles a second, it is easy to show that after eight or nine hours it would have passed more under the influence of the sun than it was under that of the globe from which it had taken its rise. ”

“ If two particles are carried with uniform motion, but each with a different speed, the distances covered by them during unequal intervals of time bear to each other the compound ratio of the speeds and time intervals. ”

“ Galileo here proposes to employ as a standard of velocity the terminal speed of a body falling freely from a given height. [Trans.]
[* ] In modern mechanics this well-known theorem assumes the following form: The speed of a projectile at any point is that produced by a fall from the directrix. ”

“ To some extent this, of course, may be due to the fact that to obtain any increment of speed a more than corresponding increment of force must be put forth, as is exemplified by the fact that an oarsman, to increase his speed from two to four miles an hour, must use more than twice the amount of force, and to increase his speed to six miles an hour, must use a still more disproportionate amount of force. ”

“ The inventor claims that it is able to maintain a speed of a mile in three minutes, and that the extraordinary time of a half mile in one minute and forty-five seconds, has been made upon a country road. ”

“ It is precisely because its speed through water is reduced that the velocity of the water will affect the velocity of the light, thereby permitting us to test out the relativistic law of the composition of velocities. ”

“ This expression may be used to find rv when the total draw-bar pull is observed as well as the speed, the changes of speed and the gradient. The speed held to correspond with the resistance must be the mean speed during the change of speed. ”

“ It has frequently been asked, could a person breathe going at that rate of speed? It is not necessary to say he could, as we are constantly traveling over 1,000 miles per hour, without suffering any inconvenience, as in either case the atmosphere is carried with us. ”

“ As the velocity increases the transmitted horse power increases, but the loss from this cause rapidly increases, and there will be one speed for every belt at which the horse power transmitted is a maximum. ”

“ Now, if all cars were going at the same speed, you could calculate with great accuracy the time taken for any one car to go around the track, or from the finish line to the backstretch, or through the spray sector, and so on. ”

“ We can travel like the wind from place to place, because in measuring time we can measure speed, and therefore we can make speed safe and possible. We can talk to a friend a thousand miles away, or signal by electric waves around the world. ”

“ Then the motorman releases the wizard car and the speed is steady and terrible until the car dashes past the center of gravity, after which the speed slackens at a regular rate. The car of its own momentum forces its way far toward the opposite surface of their earth. ”

“ Uniform.—A body has uniform motion when its speed and direction of motion do not change. Uniform motion for extended periods is rarely observed. A train may cover, on an average, 40 miles per hour but during each hour its speed may rise and fall. ”

“ He is only aware that he has been gently turned round a little two or three times. Now let the speed of rotation be slackened. He has a sensation of being gently turned round a little in the opposite direction. Each time the speed is lessened he has this sense of being turned the reverse way. From these experiments we see that what we are conscious of is change of rate of rotation, or, in technical language, acceleration, positive or negative.
Fig. 30.—Diagram of semicircular canals. ”

“ Now it is found that when the speed approaches that of light, 186,000 miles or 3 x 1010 centimetres per second, the energy is higher than it should be if it followed the usual rule, viz. energy is equal to half the mass multiplied by the square of the velocity. ”

“ And again,—“We have spoken of vehicles travelling at twenty miles an hour; but we see no reason for thinking that, in the progress of improvement, a much higher velocity might not be found practicable; and in twenty years hence a shopkeeper or mechanic, on the most ordinary occasion, may probably travel with a speed that would leave the fleetest courser behind.” ”

“ The next mile is two seconds slower, but the speed is more than maintained on the third mile. Reduced to ordinary speed figures, this means that we are making something like seventy miles an hour, and doing vastly better than was even anticipated. ”

“ The smaller the sustaining surface, the higher the speed. That was the law discovered by Langley. And I've applied it. I can rise when the air is calm and full of holes, and I can rise when its boiling, and by my control of my plane areas I can come pretty close to making any speed I want. ”