Momentum - mavuto ndi mayankho

1. Mpira wa 0.5-kg umayenda pa 2 m/s. Kenako mpirawo umamenyedwa ndi mphamvu F moyang'anizana ndi komwe mpirawo ukupita , kotero liwiro la mpirawo limasinthidwa kukhala 6 m/s . Mpirawo umakumana ndi wogunda kwa 0.01 sekondi, kodi kusintha kwa mphamvu ya mpirawo ndi kotani?

Zodziwika:

Kulemera kwa mpira (m) = 0.5 kg

Liwiro loyambirira (v _o ) = 2 m/s

Liwiro lomaliza (v _t ) = -6 m/s

Nthawi yopuma (t) = sekondi imodzi

Kufunidwa: Kusintha kwa mphamvu

Yankho:

∆p = mv _t – mv _o = m (v _t – v _o )

∆p = (0.5 kg)(- 6 m/s – 2 m/s)

∆p = (0.5 kg)(-8)

∆p = 4 kg m/s

2. Chinthu cha magalamu 100 chimayenda pa liwiro la 5 m/s. Mphamvu F imagwira ntchito kwa masekondi 0.2 kuti iyimitse chinthucho. Dziwani kukula kwa mphamvu F.

Zodziwika:

Kulemera kwa chinthu (m) = magalamu 100 = 100/1000 = 0.1 kg

Liwiro loyambirira (v _o ) = 5 m/s

Liwiro lomaliza (v _t ) = 0

Nthawi yopuma (Δt) = masekondi 0.2

Kufunidwa: Kukula kwa mphamvu F

Yankho:

Ine = ΔP

F (Δt) = m (v _t – vo _o )

F (0.2) = 0.1 (0 – 5)

F (0.2) = 0.1 (– 5)

F (0.2) = -0,5

F = -0,5 / 0.2

F = -2.5N

Kukula kwa mphamvu F = 2.5 Newtons. Chizindikiro chochotsera chimasonyeza njira ya mphamvu mosiyana ndi njira ya chinthucho.

3. Mpira wa magalamu 100 umagwa momasuka kuchokera kutalika kwa masentimita 20 popanda liwiro loyamba kenako mpirawo umagunda pansi. Pambuyo poti wagundana, mpirawo umaonekera mmwamba (kuthamanga chifukwa cha mphamvu yokoka ndi 10 ms ^-2 ). Kodi kusintha kwa mphamvu ya mpira ndi kotani?

Zodziwika:

Kulemera kwa mpira (m) = 100 magalamu = 0.1 kg

Kutalika (h) = 20 cm = 0.2 mamita

Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ²

Liwiro la mpira ukagunda pansi (v _t ) = 1 m/s

Kufunidwa: Kusintha kwa mphamvu

Yankho:

Liwiro la mpira musanagunde (vo _o )

Werengerani liwiro la mpira musanagunde pogwiritsa ntchito equation ya free fall movement. Yodziwika: kutalika kwa mpira (h) = 0.2 metres, kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ² . Yofunidwa: liwiro la mpira ukagunda pansi.

v ² = 2 gh

v ² = 2 (10)(0.2) = 4

v = √4 = -2 m/s

Chizindikiro chochotsera chimasonyeza kuti komwe mpira ukupita musanagunde kuli kosiyana ndi komwe mpira ukupita pambuyo pa kugundana.

Kusintha kwa mphamvu ya mpira (Δp)

Δp = mv _t – mv _o = m (v _t – v _o )

Δp = (0.1)(1 – (-2)) = (0.1)(1 + 2) = (0.1)(3) = 0.3 Sekondi ya Newton

4. Chinthu chomwe poyamba chili pamalo opumulira, chimaphulika m'magawo awiri ndi chiŵerengero cha 3: 2. Gawo lalikulu la kulemera limaponyedwa pa liwiro la 20 m/s. Kodi liwiro la gawo laling'ono ndi lotani ?

Zodziwika:

Kulemera kwa chinthu 1 chisanachitike kuphulika = m

Liwiro la chinthu 1 chisanachitike kuphulika = 0 (chinthu chili pamalo pake)

Kulemera kwa gawo lalikulu pambuyo pa kuphulika (m ₁ ) = 3m

Kulemera kwa gawo laling'ono pambuyo pa kuphulika (m2 ₎ = 2m

Liwiro la gawo lalikulu pambuyo pa kuphulika (v ₁ ') = 20 m/s

Kufunidwa: Liwiro la gawo laling'ono pambuyo pa kuphulika (v ₂ ')

Yankho:

Kuyerekeza kwa lamulo la kusunga mphamvu:

m ₁ v ₁ = m ₁ v ₁ ' + m ₂ v ₂ '

(m) (0) = (3m)(20) + (2m) v ₂ '

0 = 60m + (2m) v ₂ '

60m = -2m v ₂ '

60 = -2 v ₂ '

v ₂ ' = -60/2

v ₂ ' = -30 m/s

Chizindikiro chochotsera chimasonyeza kuti mbali yaying'ono ikusiyana ndi mbali yaikulu.

Kodi mphamvu ya zinthu ndi chiyani?
- Yankho: Momentum ndi kuchuluka kwa vekitala komwe kumayimira chinthu chomwe chimachokera ku kulemera kwake komanso liwiro lake. Kumasonyeza komwe chikuyenda komanso komwe chikuyenda ndipo nthawi zambiri kumaimiridwa ndi $p$ , yotanthauzidwa ngati $p = m v$ .
Kodi mphamvu ya galimoto imasiyana bwanji ndi liwiro?
- Yankho: Ngakhale kuti mphamvu ndi liwiro zonse ndi kuchuluka kwa vekitala komwe kumagwirizana ndi kuyenda, liwiro limangofotokoza liwiro ndi komwe chinthu chikuyenda, pomwe mphamvu imaganizira kulemera kwa chinthucho ndi liwiro lake. Mphamvu imapereka muyeso wa momwe zimakhalira zovuta kuyimitsa chinthu choyenda.
Kodi mfundo yosungira mphamvu ndi iti?
- Yankho: Mfundo yosungira mphamvu imati mu dongosolo lokhalokha, mphamvu yonse isanachitike chochitika (monga kugundana) iyenera kukhala yofanana ndi mphamvu yonse pambuyo pa chochitikacho, bola ngati palibe mphamvu zakunja zomwe zimachita pa dongosololi.
Kodi kutengeka maganizo kumakhudzana bwanji ndi mphamvu?
- Yankho: Mphamvu ndi kusintha kwa mphamvu ya chinthu pamene mphamvu ikugwiritsidwa ntchito pa nthawi inayake. Imaperekedwa ndi zotsatira za mphamvuyo ndi nthawi yomwe imagwira ntchito, ndipo imafanana ndi kusintha kwa mphamvu: $Pewani = F \times Δ t = Δ p$ .
N’chifukwa chiyani ma airbag m’magalimoto amathandiza kupewa kuvulala panthawi ya ngozi?
- Yankho: Ma airbags amawonjezera nthawi yomwe mphamvuyo imagwirira ntchito pa munthu amene ali pa ngozi. Izi zimachepetsa mphamvu yomwe munthuyo amakumana nayo. Chifukwa cha ubale wa mphamvu ndi mphamvu, kufalitsa kusintha kwa mphamvuyo kwa nthawi yayitali kumachepetsa mphamvuyo, zomwe zimathandiza kupewa kuvulala.
Kodi kusiyana pakati pa kugwedezeka kwa elastic ndi inelastic ndi kotani pankhani ya mphamvu ya momentum ndi kinetic?
- Yankho: Mu kugongana kwa elastic ndi inelastic, mphamvu yamagetsi imasungidwa. Komabe, mu kugongana kwa elastic, mphamvu yonse ya kinetic imasungidwanso, pomwe mu kugongana kwa inelastic, sizisungidwa.
Kodi mphamvu ya mfuti imasungidwa bwanji pamene mfuti ikubwerera m'mbuyo ikawomberedwa?
- Yankho: Mfuti ikawomberedwa, chipolopolo chimapita patsogolo ndi mphamvu inayake. Kuti chisunge mphamvu mu dongosolo lodzipatula (poganiza kuti mphamvu zakunja monga kukana mpweya ndizochepa), mfutiyo iyenera kusuntha mmbuyo ndi mphamvu yofanana komanso yotsutsana. Kusuntha kumeneku kumadziwika kuti kubwerera mmbuyo.
Nchifukwa chiyani zinthu za misa yosiyanasiyana zimagwa pamlingo womwewo mu vacuum koma zimakhala ndi nthawi zosiyana?
- Yankho: Mu vacuum, kuthamanga kwa mphamvu yokoka kumakhala kofanana pa zinthu zonse mosasamala kanthu za kulemera kwawo. Chifukwa chake, misa yosiyanasiyana imagwa pamlingo womwewo. Komabe, mphamvu imadalira liwiro ndi kulemera. Popeza mphamvu ndi $p = m v$ , zinthu ziwiri zokhala ndi kulemera kosiyana koma liwiro lofanana lidzakhala ndi mphindi yosiyana.
Kodi lamulo lachitatu la Newton likugwirizana bwanji ndi kusunga mphamvu?
- Yankho: Lamulo lachitatu la Newton limati pa chilichonse chomwe chimachitika, pamakhala kuchitapo kanthu kofanana komanso kosiyana. Zinthu ziwiri zikamagwirira ntchito limodzi, zimakhala ndi mphamvu zofanana komanso zotsutsana kwa nthawi imodzi, zomwe zikutanthauza kuti zimakumana ndi kusintha kofanana komanso kosiyana kwa mphamvu. Izi zimapangitsa kuti mphamvu yonse isanayambe kugwirirana ikhale yofanana ndi mphamvu yonse pambuyo pake, motero kusunga mphamvu.
N’chifukwa chiyani kuli kosavuta kuyimitsa njinga yoyenda kuposa galimoto yoyenda, ngakhale ikuyenda pa liwiro lomwelo?

Yankho: Ngakhale njinga ndi galimoto zingakhale ndi liwiro lofanana, mphamvu zawo zimasiyana chifukwa cha kulemera kwawo kosiyana. Mphamvu zimadalira liwiro ndi kulemera kwawo. Galimoto, yomwe ndi yayikulu kwambiri kuposa njinga, imakhala ndi mphamvu zambiri pa liwiro lomwelo. Chifukwa chake, mphamvu yayikulu (kapena kusintha kwa mphamvu) imafunika kuti galimoto iyimitse poyerekeza ndi njinga.