A Manual of Applied Mechanics

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Charles Griffin and Company, 1872 - 648 من الصفحات
 

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الصفحة 135 - be the angles made by the lines of action of the supporting forces with that of the resultant of the load ; then because each side of a triangle is proportional to the sine of the angle between the other two,
الصفحة 3 - philosopher, speedily produced a complete revolution throughout the department which was under his direction. He devoted himself to the task with an activity which left him no time to spare for those pursuits in which he had surpassed Archimedes and Galileo. Till the great work was completely done, he resisted firmly, and almost
الصفحة 5 - engineer who has to lift a great mass of real granite by the instrumentality of real timber and real hemp, should absolutely rely on the propositions which he finds in treatises on Dynamics, and should make no allowance for the imperfection of his materials, his whole apparatus
الصفحة 3 - every attempt that was made by men of science, here or on the Continent, to draw him away from his official duties."* Then the historian proceeds to detail the results of Newton's exertions, and shows, that within a short time after his appointment, the weekly amount of the coinage of silver was increased to
الصفحة 15 - Force is an action between two bodies, either causing or tending to cause change in their relative rest or motion. The notion of force is first obtained directly by sensation; for the forces exerted by the voluntary muscles can be felt. The existence of forces other than muscular tension is inferred from their
الصفحة 56 - being a constant. Let x\, y¡, z, be the co-ordinates of the centre of gravity of a flat plate having its middle plane coincident with the given cross-section. Then, by reasoning similar to that of Articles 74 and 78, we find the following results for the whole body :— volume weight V
الصفحة 273 - consistent with safety ; that is, with the retention of the strength of the material unimpaired. A stress exceeding the proof strength of the material, although it may not produce instant fracture, produces fracture eventually by long-continued application and frequent repetition. Strength, whether ultimate or proof, is the product of two quantities, which may be called
الصفحة 606 - are overcome in performing useful work and lost work respectively. 660. The Efficiency of a machine is a fraction expressing the ratio of the useful work to the whole work performed, which is equal to the energy expended. The limit to the efficiency of a machine is unity, denoting the efficiency of a perfect
الصفحة 5 - beams, wheels, and ropes, would soon come down in ruin, and with all his geometrical skill, he would be found a far inferior builder to those painted barbarians who, though they never heard of the parallelogram of forces, managed to pile up

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