. The Cambridge course of elementary natural philosophy; being the demonstrations of the propositions in mechanics and hydrostatics in which those persons who are not candidates for honours are examined for the degree of rds on C will be 2 P(Prop, n); wherefore the weight (W) which acts down-wards at C and is supported by this pressure, is = 2P; or P : W :: 1 : , In the single moveable pulley, &c. £Cor. The pressure produced at C by the forces Pand P acting at A and B is perpendicular to AB, orparallel to AP and BR (Art. 18. Ax. i.); wherefore theline of action of the We
. The Cambridge course of elementary natural philosophy; being the demonstrations of the propositions in mechanics and hydrostatics in which those persons who are not candidates for honours are examined for the degree of rds on C will be 2 P(Prop, n); wherefore the weight (W) which acts down-wards at C and is supported by this pressure, is = 2P; or P : W :: 1 : , In the single moveable pulley, &c. £Cor. The pressure produced at C by the forces Pand P acting at A and B is perpendicular to AB, orparallel to AP and BR (Art. 18. Ax. i.); wherefore theline of action of the Weight is perpendicular to AB, orparallel to AP and BR. And therefore since in a caseof equilibrium the strings are parallel to the line in whichthe weight acts, if the Weight be a heavy body hangingfreely from C, AP and BR are vertical.] 33. Pitop. xii. In a system in which the samestring passes round any number of pulleys, and theparts of it between the pulleys are parallel, there isan equilibrium when (P) : Weight (TF) :: 1 :number of strings at the lower block. [In this Proposition, as in Prop. XI., the Power and the Weight aresupposed to act in a direction parallel to that of the strings.] 32 MECHANICS;. Because there is equilibrium, the portionsof the string which lie on either side of anypulley must be pulled by equal forces; andsince the outside portion, to which thepower is applied, is acted on by a force P,each portion is therefore pulled by a forceP. Wherefore the part of the weight that issustained at A is (Prop, xi.) 2P; and thesame is true with respect to the pulley B;and so on for every other pulley at thelower block. If, therefore, there be n pul-leys at the lower block, W, the whole weightsupported, will be n x 2P; or, W=2n P; P_J_ ; w~2?i P : W :: 1 : 2?i :: 1 : number ofstrings at the lower block. Wherefore, In a system, &c. 34. Prop. xiii. In a system where each pulleyhangs by a separate string and the strings are parallel,there is an equil
Size: 878px × 2848px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, bookpub, booksubjecthydrostatics
