Mechanics of engineeringComprising statics and dynamics of solids: and the mechanics of the materials of constructions, or strength and elasticity of beams, columns, arches, shafts, etc . f axle gives Pr = Pr, , P = P = ten-sion in the cord. Hence the pressure P at the axle bisectsthe angle a, and therefore if a weighted pulley rides upon acord ABC, Fig. 47, its position of equilibrium, B, may befound by cutting the vertical through A by an arc of radiusCD = length of cord, and centre at (7, and drawing a horizon-tal through the middle of AD to cut CD in B. A smoothring would serve as well
Mechanics of engineeringComprising statics and dynamics of solids: and the mechanics of the materials of constructions, or strength and elasticity of beams, columns, arches, shafts, etc . f axle gives Pr = Pr, , P = P = ten-sion in the cord. Hence the pressure P at the axle bisectsthe angle a, and therefore if a weighted pulley rides upon acord ABC, Fig. 47, its position of equilibrium, B, may befound by cutting the vertical through A by an arc of radiusCD = length of cord, and centre at (7, and drawing a horizon-tal through the middle of AD to cut CD in B. A smoothring would serve as well as the pulley ; this would be a slip-knot. MW//////c 42. If three cords meet at afxed knot, and are in equilib-rium, the tension in any one is the equal andopposite of the resultant of those in the othertwo. 43. Tackle.—If a cord is continuous over anumber of sheaves in blocks forming a tackle,neglecting the weight of the cord and blocks andfriction of any sort, we may easily find the ratiobetween the cord-tension P and the weight to besustained. , Fig. 48, regarding all the straightcords as vertical and considering the block Bfree, we have, Fig. 49 (from 2Y= 0), 4P — G G. = 0,. The stress on the support C will = 5P. 44 MECHANICS OF ENGINEERING.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectenginee, bookyear1888
