. Encyclopædia britannica; or, A dictionary of arts, sciences, and miscellaneous literature. at particle,that is, a force which, when compounded with the in-herent force of its primitive motion, the neurmotion ; that is (by this theorem), a forCe which alonewould have caufed it to turn round a third axis B b,wilh a rotation making the other conftiluent of the actual rotation roiUid Cc, This rauft be confidered as one of the mod important *5propofitions in dynamics, and gives a great exterrfidh tothe doctrine 0/the coicpolilion of motion. We fee thatrotations are compounded in the fam
. Encyclopædia britannica; or, A dictionary of arts, sciences, and miscellaneous literature. at particle,that is, a force which, when compounded with the in-herent force of its primitive motion, the neurmotion ; that is (by this theorem), a forCe which alonewould have caufed it to turn round a third axis B b,wilh a rotation making the other conftiluent of the actual rotation roiUid Cc, This rauft be confidered as one of the mod important *5propofitions in dynamics, and gives a great exterrfidh tothe doctrine 0/the coicpolilion of motion. We fee thatrotations are compounded in the fame manner as othermotions, and it is estremely eafy to difcover the. We have only to fuppofe a fphere defcrihedround the centre of the body ; and the equator of thisfphere correfponding to any primitive pofiiion of theaxis of rotation gives us the direftion and velocity ofthe particles fituated in it. Let another great circlecut this equator in any point ; it will be the eqi:atoref niiolhtr lotation. Set off an arch of each f»om the paiirt ROTATION. I>l„.r C(fCI-.\Sl. >/«.//. y?. - . /f^ J^r,.^./b^jfr^ ROT Beli-edinsthe p-jfitioiof the axisofiotalior poiHt of inteffefticn, proportional 10 tlie angular velo-ci:s of each rotalion, a««l coinpkte the fplierical paral-lelogram. The great circle, which is the diagonal ofthis paralielogram, ?will oe the equator of the rotation,which is. ntlually covnpouiided of tbe other two. thus m»y any tivo rotations be have given an inttance of this in the folutjon of thepfcoWcm of the P-H-ECEiilOH of the Equinoxes. .It ;.pi»ears plainly in the demonllration of this theo-rem thiit the a>fisCc is a new line in the body. Thechange of rotaiioti is not accomplillied by a transferenceof the .poles EJid equator of the former rotation to anew fituation, in which they are again the poks andequator of the rotation 5 for we lee that in the rota-4i5n round the axis C c, the particle of the body whichivas fo
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Keywords: ., bookcentury1800, bookdecade1810, booksubjectencyclo, bookyear1810
