Chinyorwa pamusoro peMoment of Force
1. Ruoko rwechirevereri
Ongorora chinhu chinotenderera, senge gonhi rekamuri. Kana gonhi rakavhurwa kana kuvharwa, gonhi rinotenderera. Mahinji anobatanidza gonhi nemadziro anoshanda sechikamu chekutenderera.
Mufananidzo wemusuwo unoonekwa kubva kumusoro. Ongorora muenzaniso apo musuwo unosundwa mumasimba maviri akafanana ane hukuru negwara rakafanana, uko gwara resimba rakanangana nemusuwo. Pakutanga, musuwo unosundwa nesimba reF1,r1 kubva pachikamu chekutenderera. Zvadaro, gonhi rinosundirwa nesimba reF2,r2 kure nechikamu chekutenderera. Kunyange zvazvo hukuru negwara resimba F1 =F2, simba raF2 zvinoita kuti gonhi ritenderere nekukurumidza kupfuura simba raF1Nemamwe mashoko, simba raF2 zvinokonzera kukurumidza kukuru kwekona zvichienzaniswa nesimba raF1Unogona kuratidza izvi.
Hukuru hwekumhanya kwekona kwechinhu chinofamba hakungobatanidzwi nesimba chete asiwo kunokanganisa daro riri pakati penzvimbo dzinoshanda dzesimba nerotary axis (r). Kana divi resimba rakatarisa pamusoro pechinhu sezviri mumuenzaniso uri pamusoro, ruoko rwe lever (l) rwakaenzana nedaro riri pakati penzvimbo dzebasa nerotary axis (r). Ko kana divi resimba risingatarisa pamusoro pechinhu?
Ongorora mimwe mienzaniso miviri, sezvakaratidzwa pamufananidzo uri padivi. Kunyangwe hukuru hwesimba hwakafanana, divi resimba rakasiyana, saka ruoko rwechirevereri (l) rwakasiyanawo. MuMufananidzo 3, divi remutsara webasa rinoenderana ne axis yekutenderera kuitira kuti ruoko rwechirevereri ruve zero. Ruoko rwechirevereri runozivikanwa nekutsanangura mutsetse kubva ku axis yekutenderera kuenda kumutsetse wevashandi. Apo mutsetse we axis yekutenderera unofanirwa kunge wakamira kana kugadzira kona ye 90o nemutsara wesimba.
Tarisa mufananidzo wechipiri kuti unzwisise zviri nani equation yeruoko rwechitsiko.
chivi θ = l / r
l = r chivi θ
l = ruoko rwechirever, r = daro renzvimbo yevashandi ine axis yekutenderera.
Equation iri pamusoro apa inoshandiswa kuverenga ruoko rwe lever. Kana F yakatarisana ne r, saka kona yakagadzirwa i90o.
l = r chivi 90o = r (1)
l = r
Kana F ichienderana na r, ipapo kona yakagadzirwa i0o.
l = r chivi 0o = r (0)
iye = 0
2.2 Nguva yesimba (torsion)
2.2.1 Hukuru hwe nguva yesimba
Pamasvomhu, hukuru hwesimba renguva pfupi hunobva mukuwanda kwesimba (F) neruoko rwechirebvu (l).
τ = F l
τ = nguva yesimba (Newton metres), F = simba (Newton), l = ruoko rwechibatiso (mita)
Equation 2 inoshandiswa kuverenga hukuru hwenguva yesimba. Sisitimu yepasi rose yetorque yakafanana nebasa, asi torque haisi simba, saka unit haidi kutsiviwa neJoule. Nyanzvi dzefizikisi dzinowanzo shandisa izwi rekuti torque, nepo mainjiniya achishandisa izwi rekuti nguva yesimba.
2.2.2 Kutungamira kwesimba panguva yesimba
Nguva yesimba inhamba yevector nekuti, pamusoro pekuve nehukuru, nguva yesimba ine gwara. Kutungamira kwenguva yesimba kunozivikanwa zviri nyore uchishandisa mutemo weruoko rwerudyi. Tenderedza minwe mina yeruoko rwako rwerudyi, uku chigunwe cheruoko rwerudyi chakatsigirwa. Kutungamira kweminwe mina ndiko kutenderera kwechinhu, ukuwo gwara rinoratidzwa nechigunwe chiri kutenderera kwenguva yesimba.
Kana divi renguva yesimba riri kumusoro (richienda kudivi rey-axis) kana kurudyi (richienda kudivi rex-axis) saka divi resimba riri positive. Kusiyana neizvi, kana divi renguva yesimba riri pasi (richienda kudivi rey-axis) kana kuruboshwe (richienda kudivi re –x-axis), divi resimba riri positive. Nemamwe mashoko, kana divi rekufamba kwezvinhu riri divi rewachi, saka divi resimba riri positive. Kusiyana neizvi, kana divi rekufamba kwezvinhu riri divi rewachi, saka divi resimba riri positive.
2.2.3 Mienzaniso yezvinetso zvenguva yesimba
Matambudziko emuenzaniso 1.
Bhokisi rine urefu hwemamita masere. Padanda pane masimba matatu anoshanda, sezviri pamufananidzo. Chii chiri kukura kwenguva yesimba rinoita kuti danda ritenderere pakati paro?
Solution:
Pakati pedanda iri pakati. Kureba kwedanda iri mamita masere, saka pakati pedanda iri mamita mana kubva kumagumo edanda.
Torque 1 = F1 l1 = (10 N)(4 m) = 40 N m
Torque 1 yakanaka nekuti torque 1 inoita kuti matanda acho atenderere akatarisana newachi.
Torque 2 = F2 l2 = (10 N)(2 m) = – 20 N m
Torque 2 haina kunaka nekuti torque 2 inoita kuti danda ritenderere newachi.
Torque 3 = F3 l3 = (15 N)(2 m) = – 30 N m
Torque 3 haina kunaka nekuti torque 3 inoita kuti danda ritenderere newachi.
Torque yakakwana = 40 N m – 20 N m – 30 N m = – 10 N m
Torque inobuda inenge isina kunaka, izvi zvinoratidza kuti divi rekutenderera kwedanda rinotenderera wachi.
Matambudziko emuenzaniso 2.
F1 = 10 N, F2 = 15 N, F3 = 15 N uye F4 = 10 N, shanda patsvimbo yeABCD sezvakaratidzwa mumufananidzo. Kureba kwetsvimbo ABCD mamita makumi maviri. Kana huremu hwetsvimbo hukasatariswa, axis yekutenderera iri panzvimbo D ndiyo inosarudza hukuru hwenguva yesimba.
Solution:
Mubvunzo wedambudziko iri ndewekuti chii chinonzi net torque inokonzera kuti beam itenderere, uko axis yekutenderera iri panzvimbo D.
Torque 1 = F1 l1 = (10 N)(15 m) = 150 N m
Torque 1 yakanaka nekuti torque 1 inoita kuti danda ritenderere
yakatarisana nekwakanangana newachi.
Torque 2 = F2 l2 = (15 N)(5 m) = -75 N m
Torque 2 haina kunaka nekuti torque 2 inoita kuti danda ritenderere nenzira yewachi.
Torque 3 = F3 l3 = (15 N)(0 m) = 0 N m
Torque 3 haina zero nekuti F3 inoenderana ne axis yekutenderera.
Torque 4 = F4 l4 = (10 N)(5 m) = 50 N m
Torque 4 yakanaka nekuti torque 4 inoita kuti danda ritenderere nenzira dzakasiyana zvichienderana newachi.
Torque yakakwana = 150 N m – 75 N m + 50 N m = 125 N m
Torque ye net yakanaka, saka nzira yekutenderera kwedanda iri yakatarisana nenzira yekutarisa wachi.
