# The Essential Elements of Practical Mechanics, Based on the Principle of Work: Designed for Engineering Students

E. & F. N. Spon, 1867 - 360 ページ

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209 ページ - ... engineer, to fix upon that degree of obliquity which shall produce the greatest effect. Each bar is considered to perform its part in supporting the load, in proportion to its distance from the abutment, drawn into the sine of the angle of its direction, so that the entire series of suspending bars, transmits the same tension to the points of support as would be transmitted by a single bar reaching from thence to the middle of the bridge.
75 ページ - Divide that part of the stroke through which the expansion takes place, into any even number of equal parts, and calculate the pressure per square inch upon the piston at each division of the stroke ; take the sum of the extreme pressures in pounds per square inch, four times the sum of the even pressures, and twice the sum of the odd pressures ; multiply the sum of all these by...
271 ページ - Taking 1•292697 grammes for the weight of a litre of air under the parallel of 45° latitude, and at the same distance from the centre of the earth as that at which...
37 ページ - Every heavy body is composed of an indefinite number of particles, each of which is acted upon by the force of gravity in a direction perpendicular to the horizon. The sum of all these parallel forces is evidently the weight of the body.
249 ページ - ... the centres of gravity of the parallelogram, triangle, and trapezoid, which are vertical sections of the respective solids.
95 ページ - ... 2. From what height must a body fall to acquire a velocity of 1200 feet per, second ? 660_i-8=82.5 and 82.5x82.5= 6806.25ft= 1AV mi'es, Ans.
98 ページ - Ex. 7. A train weighing 60 tons, has a velocity of 40 miles per hour when the steam is turned off, how far will it ascend an incline of 1 in 100, taking friction at 8 Ibs. per ton ? Ans. -74 miles. In this example the work of gravity must be added to the work of friction to obtain the total work of the resistance. Ex. 8. Required the same as in the last example, when the velocity is 20 miles, and the incline has a rise of 1 in 30.
28 ページ - In a lever of the second kind, the weight is between the fulcrum and the power.
210 ページ - Ibs., or 136^\$\$\$ tons nett, being over a ton for each foot in length of the bridge. This burden was tried at about eight miles per hour, and the deflections, according to gauges properly set and reliable in their action, were at centre post, If", and at the first post from abutment nine-sixteenths of an inch.
105 ページ - Y/JJ ; and in a plane rim, like the rim of a fly-wheel, it is equal to the square root of one-half the sum of the squares of the radii forming the ring.