An Introduction to Natural Philosophy: Designed as a Text-book for the Use of Students in CollegeCollins & Brother, 1861 - 456 pages |
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Common terms and phrases
angle of friction applied axis axle ball beam body falling called center of gravity centrifugal force circumference column common center compressed curve cycloid cylinder density depth descending diameter diminished direction distance diurnal motion earth effect elastic electricity elevation equal equilibrium feet per second fluid force of gravity friction fulcrum given greater Hence horizontal horizontal plane inches inclined plane increased length lever machine magnet mechanical Mechanical Philosophy miles momentum motion move opposite parabola parallel particles passes pendulum perpendicular piston pole pounds pressure principle produce pulley radius ratio rays refraction represent resistance rest revolve rope screw side sine solid space described specific gravity square straight line strength suppose surface sustained tion triangle tube uniform varies velocity vertical vibrations waves weight wheel wheel and axle wind
Popular passages
Page 178 - ... for the purpose to which it is to be applied. In tools intended for cutting wood, the angle is generally about 30° ; for iron it is from 50° to 60° ; and for brass, from 80° to 90°. Tools which act by pressure may be made more acute than those which are driven by a blow ; and, in general, the softer and more yielding the substance to be divided is, and the less the power required to act upon it, the more acute the wedge may be constructed.* 286.
Page 136 - A man in a boat pulling a rope attached to a large ship, seems only to move the boat: but he really moves the ship a little, for...
Page 99 - CIRCULAR arcs, is to the time down half the length of the pendulum, as the circumference of a circle to its diameter ; and therefore, within moderate limits, the time will be the same, whether the arc of vibration be larger or smaller.
Page 186 - The cutting tool, shaped according to the pattern to be executed, is attached to the end of a screw; and the metal being held in a proper position beneath it, the Fly is made to urge the tool downwards with such force as to stamp out pieces of the required figure. When the pattern is complicated, and it is necessary to preserve with exactness the relative situation of its different parts...
Page 186 - ... immense force against the substance destined to receive the impression. Some engines used in coining have flies with arms four feet long, bearing one hundred weight at each of their extremities. By turning such an arm at the rate of one entire circumference in a second, the die will be driven against the metal with the same force as that with which 7500 pounds weight would fall from the height of 16 feet ; an enormous power, if the simplicity and compactness of the machine be considered.
Page 118 - Two equal circular disks with smooth edges, placed on their flat sides in the corner between two smooth vertical planes inclined at a given angle, touch each other in the line bisecting the angle. Find the radius of the least disk which may be pressed between them without causing them to separate. LXXIV. If two scales, one containing a weight P and the other a weight Q, be suspended by a string over a rough sphere, Q2...
Page 164 - A wheel and axle constructed in this manner is equivalent to an ordinary one, in which the wheel has the same...
Page 155 - Tools are the simplest instruments of art ; these when complicated in their structure, become machines ; and machines when they act with great power, take the name of engines. Among the ancients, machines were confined chiefly to the purposes of architecture and war ; and they were moved almost exclusively by the strength of animals. Thus, in building one of the great Pyramids of Egypt, vast masses of stones were raised to a great height, amounting together to 10,400,000 tons.
Page 233 - London; and to fall these eight hundred feet, in its long course, the water requires more than a month. The great river Magdalena, in South America, running for a thousand miles between two ridges of the Andes, falls only five hundred feet in all that distance.
Page 163 - To investigate the proportion of the power to the weight in this case, let fig. 97. represent a section of the apparatus at right angles to the axis. The weight is equally suspended by the two parts of the rope, S and S', and therefore each part is stretched by a force equal to half the weight. The moment of the force, which stretches the rope S, is half the weight multiplied by the radius of the thinner part of the axle.