Nkhani yokhudza lamulo la Newton loyendetsa zinthu
1. Tanthauzo la mphamvu
Mphamvu ndi chinthu chomwe chimapangitsa kuti zinthu ziziyenda mofulumira. Mwa kuyankhula kwina, mphamvu ndi chinthu chomwe chimayenda, kuyimitsa, kapena kusintha njira yoyendera chinthu. Mphamvu ndi kuchuluka kwa vekitala, motero, ili ndi kukula ndi njira. Chizindikiro cha mphamvu ndi F (Mphamvu). F ndi chizindikiro cha mphamvu. Pali mitundu ingapo ya mphamvu ndipo si mphamvu zonse zomwe zili ndi chizindikiro F. Gawo la dongosolo lapadziko lonse lapansi ndi kg m/s2 aka Newton.
2. Tanthauzo la mphamvu ya ukonde
Mphamvu yochokera (ΣF) ndi chiŵerengero cha mphamvu zonse zomwe zimagwira ntchito pa chinthu. Mphamvu ndi kuchuluka kwa vekitala, kotero mphamvu yonse imawerengedwa kutengera lamulo lowonjezera vekitala.
Mphamvu yonse = 10 Newtons, komwe mphamvu yonse ikupita kumanja.
Mphamvu yonse = 8 Newtons, komwe mphamvu yonse ikupita kumanja.
Mphamvu yonse = 0
Mphamvu yonse = 0
3. Malamulo a Newton okhudza kuyenda
Malamulo a Newton oyendera ndi malamulo a sayansi ya zakuthambo okhudza kuyenda kwa chinthu chomwe chinaperekedwa ndi katswiri wa sayansi ya zakuthambo wa ku England, Isaac Newton.
3.1 Lamulo Loyamba la Newton
Lamulo Loyamba la Newton limati chinthu chilichonse chomwe chili pampando chiyenera kukhala pampando, kapena kuti chinthu chilichonse chomwe chikuyenda molunjika pa liwiro losasintha
idzapitiriza kuyenda molunjika pa liwiro losasintha ngati mphamvu yonse yomwe ikugwira ntchito pa chinthucho ndi zero.
ΣF = 0
Chiganizo ichi ndi chiganizo cha masamu kuchokera mu lamulo loyamba la Newton.
Onani chinthu chozungulira inu, monga tebulo kapena mwala kapena chinthu chilichonse. Tebulo lomwe lili pamalo pake lidzakhalabe pamalo pake ngati silisunthidwa kapena silinapatsidwe mphamvu yakunja monga kukankhira kapena kukoka. Kodi palibe mphamvu yomwe imagwira ntchito pa matebulo kapena miyala kapena zinthu zomwe zili pamalo pake? Pali mphamvu yomwe imagwira ntchito pa chinthucho, koma kuchuluka kwa mphamvu zonse zomwe zikugwira ntchito pa chinthucho kapena mphamvu yonse ndi zero. Mphamvu zomwe zikugwira ntchito pa zinthu zomwe zidakali pamwamba pa mapulaneti monga dziko lapansi ndi mphamvu yokoka (w) ndi mphamvu yachibadwa (N). Njira ya mphamvu yokoka ndi yolunjika pakati pa dziko lapansi, njira ya mphamvu yachibadwa ndi yolunjika mmwamba. Kukula kwa mphamvu ziwirizi ndi kofanana, koma zili ndi njira yosiyana, kotero mphamvu yonse ndi yofanana ndi zero.
Nanga bwanji zinthu zomwe zikuyenda molunjika ndi liwiro losalekeza? Kuti timvetse vutoli, tiyerekeze kuti mwakankhira chinthu, mwachitsanzo, chidutswa cha chitsulo, pamwamba pa pansi. Pambuyo pokankhira, chitsulocho chimachepa ndikuyima chifukwa cha kukangana. Kuti zidutswa zachitsulo zisunthe patali kapena kupitirira apo, ndiye kuti muyenera kusalala pamwamba ndi pamwamba pa mbale yachitsulo. Ngati pamwamba pa pansi pali posalala ndipo palibe kukangana, mbale yachitsuloyo idzapitiriza kuyenda osaima. Kodi palibe mphamvu yomwe ikugwira ntchito pa mbale yachitsulo yomwe ikuyenda pamwamba pa pansi pabwino komanso losalala? Pali mphamvu zomwe zimagwira ntchito pa mbale zachitsulo, zomwe ndi mphamvu yokoka ndi mphamvu yachibadwa. Mphamvu zonsezi zimagwira ntchito molunjika ndipo sizikhudza kuyenda kwa mbale zachitsulo molunjika ngati pansi pali posalala.
3.2 Lamulo Lachiwiri la Newton
Lamulo Lachiwiri la Newton limati ngati mphamvu yonse yomwe ikugwira ntchito pa chinthu siili ndi zero, ndiye kuti chinthucho chidzathamanga. Kukula kwa kuthamanga kumafanana ndi kukula kwa mphamvu yonse ndipo motsutsana ndi kulemera kwa chinthucho. Kulunjika kwa kuthamanga ndi kofanana ndi komwe mphamvu yonse imapita.
ΣF = ma
ΣF = mphamvu yonse (kg m/s 2 ), m = kulemera (kg), a = kuthamanga (m/s 2 )
Equation 1.2 ndi chiganizo cha masamu kuchokera ku lamulo lachiwiri la Newton.
Ngati kuthamanga kuli kofanana ndi zero (a = 0) ndiye kuti equation 1.2 imasintha kukhala equation 1.1. Chifukwa chake, lamulo loyamba la Newton ndi chitsanzo chapadera cha lamulo lachiwiri la Newton. Kutengera equation 1.2, zatsimikiziridwa kuti mphamvu ikakhala yayikulu, kuthamanga kumakulirakulira. Mosiyana ndi zimenezi, kulemera kumakulirakulira, kuthamanga kumacheperachepera. Ubale pakati pa mphamvu, kulemera, ndi kuthamanga umamveka bwino mutachita kafukufuku wokhudza izi.
Chitsanzo cha vuto 1:
Dziwani kukula ndi komwe zinthu zikuyendera mofulumira kutengera chithunzi chomwe chili pamwambapa…
yankho;
ΣF = ma
4 kg m/s 2 = (1 kg) a
a = 4 kg m/s 2 : 1 kg = 4 m/s 2
Kukula kwa kuthamanga = 4 m/s 2 , komwe kuthamanga kumachokera kumanja.
Chitsanzo cha vuto 2:
Dziwani kukula ndi komwe kuthamanga kwa liwiro kumachokera pa chithunzi pamwambapa ...
yankho;
ΣF = ma
4 kg m/s 2 – 1 kg m/s 2 = (1 kg) a
3 kg m/s 2 = (1 kg) a
a = 3 kg m/s 2 : 1 kg
a = 3 m/s 2
Kukula kwa kuthamanga = 3 m/s 2 , komwe kuthamanga kumachokera kumanja.
3.2.1 Kulemera (w)
Kulemera ndi mphamvu yokoka yomwe imagwira ntchito pa chinthu chachikulu.
ΣF = ma
w = mg
Equation 1.3 ndi equation yowerengera kulemera kwa chinthu.
w = kulemera (kg m/s 2 ), m = kulemera (kg), g = kufulumira kwa mphamvu yokoka (m/s 2 ). Kukula kwa kufulumira kwa mphamvu yokoka (g) padziko lapansi ndi 9.8 m/s 2 . Kuti kuwerengetsa kukhale kosavuta, g imazunguliridwa kufika pa 10 m/s 2.
3.2.2 Mphamvu yachibadwa (N)
Mphamvu yachibadwa ndi mphamvu yomwe imagwira ntchito pa zinthu ziwiri zomwe zimagwirizana, momwe mphamvu yachibadwa imalowera molunjika pamwamba pa malo olumikizirana.
Yang'anani zinthu zomwe zili pamwamba pa tebulo. Mphamvu yokoka kapena kulemera imagwiranso ntchito pa chinthucho. Zinthu sizigwa momasuka ngati zipatso zomwe zimagwa kuchokera mumtengo chifukwa pali mphamvu yachibadwa. Kulemera (w) ndi kwachibadwa (N) ndi kofanana koma kosiyana kotero kuti mphamvu yonse pa chinthucho ndi zero.
ΣF = 0
N – w = 0
N = w
3.3 Lamulo Lachitatu la Newton
Lamulo lachitatu la Newton limati ngati chinthu 1 chimapereka mphamvu ku chinthu 2, nthawi yomweyo chinthu 2 chimapereka mphamvu ku chinthu 1. Mphamvu ziwirizi ndi zofanana, koma komwe mphamvu ziwirizi zikupita ndi kosiyana. Mphamvu imodzi imatchedwa kuchitapo kanthu, ina imatchedwa kuchitapo kanthu.
F action = – F reaction
Equation 1.3 ndi mawu a masamu ochokera mu lamulo lachitatu la Newton. Chizindikiro chotsutsa mu equation 1.3 chimafotokoza komwe mphamvuyo ikupita.
Yesani kuti mumvetse bwino lamulo lachitatu la Newton. Ngati muli ndi skateboard, kankhirani khoma mutayimirira pa skateboard. Mukakankhira khoma, skateboard imabwerera m'mbuyo. Mphamvu yanu imapita patsogolo, pomwe mphamvu ya skateboard imapita m'mbuyo.
Izi zikusonyeza kuti khoma limakukakamizaninso. Mukakankhira khoma, nthawi yomweyo, khoma limakukakamizaninso. Mphamvu yanu yokankhira imagwira ntchito pakhoma, pomwe mphamvu yokankhira khoma imagwira ntchito pa inu. Mphamvu zonse ziwiri zili chimodzimodzi koma mosiyana. Mutha kutcha mphamvu imodzi ngati zochita ndi ina ngati yankho.
Kuyesera kwina komwe kungachitike ndikupukutira buluni ya rabara ndipo buluni ya rabara ikakula chifukwa cha kudzazidwa ndi mpweya, tulutsani buluniyo. Buluniyo ikatulutsidwa, "ikuuluka". Njira yoyendera buluniyo ndi yosiyana ndi njira yotulukira mpweya kuchokera ku buluniyo. Kodi mungafotokoze bwanji izi?
Pakamwa pa buluni patulutsidwa, buluniyo imatulutsa mpweya. Nthawi yomweyo, mpweya umakankhiranso buluniyo. Mphamvu yokankhira mpweya imapangitsa buluniyo kuuluka. Mphamvu ya buluniyo imagwira ntchito ikusewera, mphamvu ya mpweya imagwira ntchito pa buluniyo. Mphamvu ziwirizi ndi zofanana, koma njira yake ndi yosiyana.
Yang'anani chithunzi 2 ndikuchiyerekeza ndi chithunzi 3. Mphamvu yachibadwa yomwe imagwira ntchito pa chinthu (N) ndi mphamvu yomwe imaperekedwa ndi malo athyathyathya, monga pamwamba pa tebulo. Nthawi yomweyo, zinthu zimaperekanso mphamvu pamwamba pa tebulo (N '). Mphamvu zonse ziwiri zachibadwa (N ndi N') zili ndi kukula kofanana, koma zili mbali zosiyana ndipo zimagwira ntchito pazinthu zosiyanasiyana. Mosiyana ndi w ndi N zomwe zili ndi kukula kofanana ndipo zimagwira ntchito pa chinthu chomwecho. Chifukwa chake N ndi N 'ndi mphamvu zochitira zinthu.
