Fabri, Honoré, Tractatus physicus de motu locali, 1646

Table of figures

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              ſunt vt radices AEAT, id eſt tempus quo percurritur AE eſt ad tem­
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              pus, quo percurritur AT, vt AE ad mediam proportionalem inter AE
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              AT, vel vt AD ad mediam proportionalem inter AD AR; quippe AD
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              eſt ad AR vt AE ad AT. </s>
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              <s id="N1D758">Galileus verò demonſtrat rationem iſtorum temporum eſſe compoſi­
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              tam ex ratione longitudinem planorum & ex ratione ſubduplicata al­
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              titudinum eorumdem permutatim accepta: pro quo obſerua à Galileo
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              rationem duplicatam appellari duplam, & ſubduplicatam appellari ſub­
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              duplam. </s>
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              <s id="N1D766">Obſeruabis denique plurima ex his colligi poſſe præſertim ex Th. 27.
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              quæ quia ſunt purè geometrica, certè phyſicę minimè competunt; aliqua
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              tamen omittere non poſſum. </s>
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              <s id="N1D770">Primò, ſi ſint duo plana inæqualia ad angulum rectum, qui ſuſtinea­
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              tur ab horizontali, determinari poſſunt tempora deſcenſuum ſit enim
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              triangulum orthogonium ABE, ita vt AE ſit horizontalis; </s>
              <s id="N1D778">ducatur B
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              G indefinita perpendicularis in baſim AE; </s>
              <s id="N1D77E">tùm FA perpendicularis in
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              AB; </s>
              <s id="N1D784">tùm FC perpendicularis in BE; </s>
              <s id="N1D788">tùm denique GE in BE; </s>
              <s id="N1D78C">dico BA
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              BFBC percurri temporibus æqualibus, item BE, BG, EG, etiam æqua­
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              libus; </s>
              <s id="N1D794">igitur tempus, quo percurritur BA eſt ad tempus quo percurri­
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              tur BE, vt tempus, quo percurritur BF ad tempus quo percurritur BG;
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              hæc porrò ſunt in ſubduplicata ratione BFBG vel BC, & BE. </s>
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              <s id="N1D79F">Secundò, ſi planum ſuſtinens angulum rectum non ſit parallelum
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              horizonti 6. res ſimiliter determinari poterit; </s>
              <s id="N1D7A5">ſit enim triangulum or­
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              thogonium ABC ex B, ducatur perpendicularis deorſum indefinitè BF,
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              tùm EA in AB, tùm DC in CB, tùm EH parallela DC, tùm GC in A
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              C; </s>
              <s id="N1D7AF">denique AG parallela BF; dico quod BABEHE AE percurren­
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              tur æqualibus temporibus item BCCDBD. </s>
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              <s id="N1D7B7">Tertiò, ſiue deſcendat ex B in C per lineam perpendicularem BC,
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              ſiue ex A per inclinatam AC, eodem modo deſcendet ſiue per CD, ſiue
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              per CE; ratio eſt clara, quia acquirit æqualem velocitatem ſiue ex A ſi­
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              ue ex B deſcendat pet Th. 20. erit autem tempus per CE ad tempus per
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              CD, vt CE ad CD per Th.23.& motus per CE ad motum per CD, vt
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              CD ad CE per Th.6. poſito initio motus in C. </s>
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              <s id="N1D7C8">Quartò, præuio motu ex A vel ex B ad C poteſt inueniri inclinata,
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              per quam mobile pergat moueri motu ſcilicet naturaliter accelerato, ita
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              vt æquali tempore illam conficiat; </s>
              <s id="N1D7D0">ſi enim BC conficiet dato tempore; </s>
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              igitur CF triplum CB conficiet tempore æquali; </s>
              <s id="N1D7D9">ſit autem planum ho­
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              rizontale EDK ad quod ex C ducendum ſit planum inclinatum, quod
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              eodem tempore percurratur, quo CF, diuidatur CF bifariam in H, & ex
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              puncto H fiat arcus CK, ducaturque CK: </s>
              <s id="N1D7E3">Dico CF & CK æquali tem­
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              pore confici per Th. 27. modò ex quiete C procedat motus: </s>
              <s id="N1D7E9">ſimiliter aſ­
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              ſumi poteſt alia horizontalis LM ducto arcu LF ex centro H; </s>
              <s id="N1D7EF">nam CL
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              & CF æquali tempore percurruntur; </s>
              <s id="N1D7F5">ſi verò præſupponatur motus præ­
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              uius ex A vel ex B, haud dubiè CK breuiori tempore percurretur, quàm
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              CF, idem dico de CL; </s>
              <s id="N1D7FD">alioqui CE & CI eodem præuio motu ſuppo </s>
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