Mechanics: Their Principles and Practical ApplicationsOliver Byrne De Witt & Davenport, 1853 - 182 Seiten |
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applied axis axle balance ball beam called centre of gravity centre of motion centre of oscillation centrifugal force circumference condition of equilibrium cord curve cycloid cylinder descend described diameter diminished direction distance effect equal equi exactly example feet per second fluid forces acting friction fulcrum Hence horizontal impact inches inclined plane increased length lever liquid load machine magnitude mass matter mechanical advantage move moveable multiplied number of teeth orifice ounces parallelogram parallelogram of forces particles pendulum perpendicular pinion placed points of suspension portion position pounds pressure proportion pulley quantity radii radius raised ratchet-wheel ratio represented resistance rest resultant revolve rope scale-pan screw second kind side simple machine solid space specific gravity square root steelyard straight line suppose surface suspended sustains tension third kind thread tion troy pound turn vertical vessel vibration virtual velocities wedge weight wheel
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Seite 178 - It is better, on this account, in graduating the bottle, to make two scratches as represented in the drawing, one at the top and the other at the bottom of the curve : this prevents any future mistake.
Seite 33 - The evolutions of the performer are found to be facilitated by holding in his hand a heavy pole. His security in this case depends, not on the centre of gravity of his body, but on that of his body and the pole taken together. This point is near the centre of the pole, so that, in fact, he may be said to hold in his hands the point on the position of which the facility of his feats depends. Without the aid of the pole the centre of gravity would be within the trunk of the body, and its position could...
Seite 46 - In drawing a nail with steel forceps or nippers, we have a good example of the advantages of using a tool: 1, the nail is seized by the teeth of steel instead of by the soft fingers: 2, instead of the griping force of the extreme fingers only, there is the force of the whole hand conveyed through the handles of the nippers: 3, the force is rendered, perhaps, six times more effective by the lever-length...
Seite 87 - ... There is, therefore, a practical limit to the increase of the power, and that degree of sharpness only is to be given to the tool which is consistent with the strength requisite 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°.
Seite 60 - ... through a space equal to the circumference of the wheel, and the weight is raised through a space equal to the circumference of the axle. Hence, the...
Seite 38 - ... is equal to the sum of the moments of the forces which tend to turn the body in the opposite direction about the same point.
Seite 67 - ... kinds, distinguished by the position which the teeth bear with respect to the axis of the wheel. When they are raised upon the edge of the wheel as in Jig.
Seite 65 - Fig. 62. may thus be at any distance apart, and may turn either the same way or contrary ways, according as the belt does or does not cross between them.
Seite 63 - ... which, as will presently be seen, form the bases for determining the form and size of the teeth. In wheel-work, therefore, the condition of equilibrium is, as expressed by the ratio above, that the power multiplied by the product of the numbers of teeth in all the wheels, is equal to the load multiplied by the product of the number of leaves in all the pinions. If, as in Fig. 32, some of the wheels and axles carry teeth, and others not, then, the effective radii of the former being measured from...
Seite 177 - ... place and rises in another. The same process is again repeated and each wave thus advances farther on, and the progressive motion is continually kept up. Each wave contains, at any one moment, particles in all possible stages of their oscillation ; some rising and some falling ; some at the top and and some at the bottom ; and the distance from any row of particles to the next row that is in precisely the same stage of oscillation, is called breadth of the wave, that is, the distance from crest...