Conversations on Natural Philosophy: In which the Elements of that Science are Familiarly ExplainedJohn Grigg, 1826 - 220 من الصفحات |
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الصفحة 33
... hour . The velocity of a body is termed relative , when compared with that of another body which is itself in motion . For instance , if one man walks at the rate of a mile an hour , and another at the rate of two miles an hour , the ...
... hour . The velocity of a body is termed relative , when compared with that of another body which is itself in motion . For instance , if one man walks at the rate of a mile an hour , and another at the rate of two miles an hour , the ...
الصفحة 34
... hours , what is your velocity in each hour ? Emily . I must divide the space , which is one hundred miles , by the time , which is twenty hours , and the answer will be five miles an hour . Then , Mrs. B. , may we not reverse this rule ...
... hours , what is your velocity in each hour ? Emily . I must divide the space , which is one hundred miles , by the time , which is twenty hours , and the answer will be five miles an hour . Then , Mrs. B. , may we not reverse this rule ...
الصفحة 39
... hour . Caroline . I now understand it perfectly , and think that I shall never forget a thing which you have rendered so clear . Mrs. B. I recommend it to you to be very careful to remem- ber the definition of the momentum of bodies ...
... hour . Caroline . I now understand it perfectly , and think that I shall never forget a thing which you have rendered so clear . Mrs. B. I recommend it to you to be very careful to remem- ber the definition of the momentum of bodies ...
الصفحة 78
... hours in performing one revolution on its axis ; in that period of time , therefore , we have a day and a night ; hence this revolution is called the earth's diurnal or daily motion ; and it is this revolution of the earth from west to ...
... hours in performing one revolution on its axis ; in that period of time , therefore , we have a day and a night ; hence this revolution is called the earth's diurnal or daily motion ; and it is this revolution of the earth from west to ...
الصفحة 83
... hours and 21 15. What other motion has the sun , and how is it proved ? 16. How may you observe the motion of a planet , by means of a fixed star ? 17. What is represented by fig . 1. plate 7 ? 18. Why are the orbits represented as ...
... hours and 21 15. What other motion has the sun , and how is it proved ? 16. How may you observe the motion of a planet , by means of a fixed star ? 17. What is represented by fig . 1. plate 7 ? 18. Why are the orbits represented as ...
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angle appear atmosphere axis ball called camera obscura Caroline cause centre of gravity circle concave mirror convex convex lens degrees diminished direction distance diurnal motion earth eclipses effect elastic Emily equal equator equilibrium equinox fixed stars fluid focus force fulcrum glass globe greater heat inclined plane length lens lever liquid longitude luminous body magnified meant mechanical power mercury meridian moon motion move nature object obliquely observe opaque body orbit parallel particles passing perfectly perpendicular planets plate 14 poles pressure produced properties proportion pulley pump quantity of matter rays fall rays of light reflected rays refracted represented resistance retina revolution revolve round rise round the sun screw shadow shine situated solar solid bodies sonorous body sound space specific gravity sphere spring sun's rays suppose surface tides tion tube understand vapour velocity vernal equinox vibrations weight wheel whilst wind zone
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الصفحة 82 - Now came still Evening on, and Twilight gray had in her sober livery all things clad : Silence accompanied ; for Beast and Bird, they to their grassy couch, these to their nests, were slunk, — all but the wakeful nightingale; she, all night long, her amorous descant sung; Silence was pleased. Now...
الصفحة x - IDE, of the said District, hath deposited in this office, the title of a book, the right whereof he claims as proprietor, in the words following, to wit : " Inductive Grammar, designed for beginners. By an Instructer." In conformity to the act of the Congress of the United States...
الصفحة 84 - Their names are Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces; the whole occupying a complete circle, or broad belt, in the heavens, called the zodiac, (plate 8.
الصفحة 64 - ... time that the axle describes a small one, therefore the power is increased in the same proportion as the circumference of the wheel is greater than that of the axle. If the velocity of the wheel is...
الصفحة 196 - The effect of a concave lens is, you know, exactly the reverse of a convex one: it renders parallel rays divergent, and those which are already divergent, still more so. By the assistance of such glasses, therefore, the rays from a distant object fall on the pupil, as divergent as those from a less distant object; and, with short-sighted people, they throw the image of a distant object back as far as the retina. Caroline. This is an excellent contrivance, indeed. Mrs.
الصفحة 67 - ... perfect smoothness or evenness in nature: polished metals, though they wear that appearance, more than any other bodies, are far from really possessing it; and their inequalities may frequently be perceived through a good magnifying glass. When, therefore, the surfaces of the two bodies come into contact, the prominent parts of the.
الصفحة 36 - ... is continually increased. When a stone falls from a height, the impulse which it receives from gravity during the first instant of its fall, would be sufficient to bring it to the ground with a uniform velocity : for, as we have observed, a body having been once acted...
الصفحة 73 - ... 1, 2, 3, 4, &c. all of which are of equal dimensions, though of very different forms ; some of them, you see, are long and narrow, others broad and short : but they each of them contain an equal quantity of space. An imaginary line drawn from the centre of the earth to that of the sun, and keeping pace with the earth in its revolution, passes over equal areas in equal times ; that is to say, if it is a month going from A to B, it will be a month going from B to C, and another from C to E, and...
الصفحة 50 - The curve-line which the ball has described, is called in geometry, a parabola; but when the ball is thrown perpendicularly upwards, it will descend perpendicularly ; because the force of projection, and that of gravity, are in the same line of direction. We have noticed the centres of magnitude, and of motion ; but I have not yet explained to you what is meant by the centre of gravity ; it is that point in a body, about which all the parts exactly balance each other ; if, therefore, that point is...
الصفحة 72 - A* (fig. 3.) its projectile force should not have given it a velocity sufficient to counterbalance that of gravity, so as to enable these powers conjointly to carry it round the sun in a circle; the earth, instead of describing the line AC, as in the former figure, will approach nearer the sun in the line A B.