Isihloko mayelana ne-Moment of Force
1. Ingalo yelever
Buyekeza into ejikelezayo, njengomnyango wegumbi. Uma umnyango uvuliwe noma uvaliwe, umnyango uyajikeleza. Amahinji axhumanisa umnyango nodonga asebenza njenge-axis yokujikeleza.
Isithombe somnyango sibonakala ngenhla. Buyekeza isibonelo lapho umnyango ucindezelwa khona ngamandla amabili afanayo anobukhulu kanye nesiqondiso esifanayo, lapho isiqondiso samandla siqonde ngqo emnyango. Ekuqaleni, umnyango ucindezelwa ngamandla ka-F1, r1 kusukela ku-axis yokujikeleza. Ngemva kwalokho, umnyango ucindezelwa ngamandla ka-F2, r2 kude ne-axis yokujikeleza. Nakuba ubukhulu kanye nesiqondiso samandla F1 =F2, amandla ka-F2 kubangela ukuthi umnyango ujikeleze ngokushesha kunamandla ka-F1Ngamanye amazwi, amandla ka-F2 kubangela ukusheshisa okukhulu kwe-angular uma kuqhathaniswa namandla ka-F1Ungakufakazela lokhu.
Ubukhulu bejubane le-angular lento ehambayo abuthonywanga nje kuphela ngamandla kodwa futhi buthonywa yibanga eliphakathi kwamaphuzu okusebenza amandla kanye ne-rotary axis (r). Uma isiqondiso samandla siqonde ngqo ebusweni bento njengasesibonelweni esingenhla, khona-ke ingalo ye-lever (l) ilingana nebanga eliphakathi kwamaphuzu okusebenza ne-axis yokujikeleza (r). Kuthiwani uma isiqondiso samandla singaqonde ngqo ebusweni bento?
Buyekeza ezinye izibonelo ezimbili, njengoba kuboniswe esithombeni ohlangothini. Nakuba ubukhulu bamandla bufana, isiqondiso samandla sihlukile, ngakho-ke ingalo ye-lever (l) nayo ihlukile. KuMfanekiso 3, isiqondiso somugqa womsebenzi wamandla sihambisana ne-axis yokujikeleza ukuze ingalo ye-lever ibe ngu-zero. Ingalo ye-lever yaziwa ngokuchaza umugqa osuka ku-axis yokujikeleza uye emgqeni wabasebenzi. Lapho umugqa we-axis yokujikeleza kumele ube oqondile noma wakhe i-engeli engu-90o ngomugqa wamandla.
Bheka isithombe 2 ukuze uqonde kangcono isibalo sengalo ye-lever.
Isono θ = l / r
l = r isono θ
l = ingalo ye-lever, r = ibanga lephuzu labasebenzi eline-axis yokujikeleza.
Isibalo esingenhla sisetshenziselwa ukubala ingalo ye-lever. Uma u-F eqondile ku-r, khona-ke i-engeli eyakhiwe ingu-90 o.
l = r sin 90 o = r (1)
l = r
Uma u-F ehambisana no-r, khona-ke i-engeli eyakhiwe ingu-0 o.
l = r sin 0 o = r (0)
l =0
2.2 Isikhathi samandla (itorque)
2.2.1 Ubukhulu besikhathi samandla
Ngokwezibalo, ubukhulu bamandla esikhashana buwumphumela wokuphindaphinda kwamandla (F) kanye nengalo ye-lever (l).
τ = F l
τ = umzuzu wamandla (imitha yeNewton), F = amandla ( Newton ), l = ingalo yelever (imitha)
Isibalo 2 sisetshenziselwa ukubala ubukhulu besikhathi samandla. Uhlelo lwamazwe ngamazwe lwe-torque lufana nomsebenzi, kodwa i-torque ayiwona amandla, ngakho-ke iyunithi ayidingi ukushintshwa nge-Joule. Izazi zefiziksi zivame ukusebenzisa igama elithi torque, kuyilapho onjiniyela besebenzisa igama elithi mzuzu wamandla.
2.2.2 Isiqondiso sesikhathi samandla
Umzuzu wamandla uyinani le-vector ngoba, ngaphezu kokuba nobukhulu, umzuzu wamandla nawo unesiqondiso. Isiqondiso somzuzu wamandla saziwa kalula kusetshenziswa umthetho wesandla sokunene. Jikelezisa iminwe emine yesandla sakho sokunene, kuyilapho isithupha sesandla sokunene sisekelwe. Isiqondiso seminwe emine siyisiqondiso sokujikeleza kwento, kuyilapho isiqondiso esiboniswe yisithupha siyisiqondiso somzuzu wamandla.
Uma isiqondiso sesikhathi samandla siphezulu (ngakwesokunene se-y) noma ngakwesokudla (ngakwesokunene se-x) khona-ke umzuzu wamandla ulungile. Ngokuphambene nalokho, uma isiqondiso sesikhathi samandla siphansi (ngakwesokunene se-y) noma ngakwesobunxele (ngakwesokunene se-x), umzuzu wamandla ulungile. Ngamanye amazwi, uma isiqondiso sokujikeleza kwezinto sihamba ngewashi, khona-ke umzuzu wamandla ulungile. Ngokuphambene nalokho, uma isiqondiso sokujikeleza kwezinto siphambene nokujikeleza kwewashi, khona-ke umzuzu wamandla ulungile.
2.2.3 Izibonelo zezinkinga zesikhathi samandla
Izinkinga zesampula 1.
Ibhulokhi inobude obungamamitha angu-8. Ebhamini kusebenza amandla amathathu, njengoba kuboniswe esithombeni. Ubukhulu bamandla buyini obubangela ukuthi ibhamini ijikeleze phakathi nendawo?
Isixazululo:
Isikhungo somshayo sitholakala phakathi nendawo. Ubude bomshayo bungamamitha ayi-8, ngakho-ke isikhungo somshayo singamamitha ama-4 ukusuka ekugcineni komshayo.
I-Torque 1 = F 1 l 1 = (10 N)(4 m) = 40 N m
I-Torque 1 inhle ngoba i-torque 1 ibangela ukuthi imisebe ijikeleze ngokuphambene ngokwewashi.
I-Torque 2 = F 2 l 2 = (10 N)(2 m) = – 20 N m
I-Torque 2 ayilungile ngoba i-torque 2 ibangela ukuthi umsebe ujikeleze ngokwewashi.
I-Torque 3 = F 3 l 3 = (15 N)(2 m) = – 30 N m
I-Torque 3 ayilungile ngoba i-torque 3 ibangela ukuthi umsebe ujikeleze ngokwewashi.
I-torque ephelele = 40 N m – 20 N m – 30 N m = – 10 N m
I-torque ephumelayo ayilungile, lokhu kubonisa ukuthi isiqondiso sokujikeleza kogongolo sihamba ngokwewashi.
Izinkinga zesampula 2.
F 1 = 10 N, F 2 = 15 N, F 3 = 15 N kanye F 4 = 10 N, sebenza endukwini ye-ABCD njengoba kuboniswe esithombeni. Ubude benduku i-ABCD bungama-20 amamitha. Uma isisindo senduku singanakwa, i-axis yokujikeleza etholakala endaweni D inquma ubukhulu besikhathi samandla.
Isixazululo:
Umbuzo walobu bunzima ukuthi iyini i-torque enetha ebangela ukuthi umsebe ujikeleze, lapho i-axis yokujikeleza itholakala khona endaweni D.
I-Torque 1 = F 1 l 1 = (10 N)(15 m) = 150 N m
I-Torque 1 ilungile ngoba i-torque 1 ibangela ukuthi umsebe ujikeleze
okuphambene nesiqondiso sokujika kwewashi.
I-Torque 2 = F 2 l 2 = (15 N)(5 m) = -75 N m
I-Torque 2 ayilungile ngoba i-torque 2 ibangela ukuthi umsebe ujikeleze ngendlela yewashi.
I-Torque 3 = F 3 l 3 = (15 N)(0 m) = 0 N m
I-Torque 3 ingu-zero ngoba i-F 3 ihambisana ne-axis yokujikeleza.
I-Torque 4 = F 4 l 4 = (10 N)(5 m) = 50 N m
I-Torque 4 ilungile ngoba i-torque 4 ibangela ukuthi umsebe ujikeleze ngezindlela eziphambene ngokwewashi.
I-torque ephelele = 150 N m – 75 N m + 50 N m = 125 N m
I-torque ephelele ilungile, ngakho-ke indlela yokujikeleza kwe-beam iphambene nendlela yokujikeleza kwewashi.
