2 Zitsanzo za mafunso okhudza mphamvu
Mphamvu ndi liwiro limene ntchito imagwiridwa usa kapena khama lopangidwa mkati mwa nthawi inayake.
Mwachidule, mphamvu ndi chiŵerengero cha khama ndi nthawi.
P = W / t
Kufotokozera: P = mphamvu (gawo Joule/sekondi), W = ntchito (Joule) ndi t = nthawi yopuma (sekondi)
Kutengera ndi equation iyi, zitha kutsimikiziridwa kuti liwiro lomwe ntchito ikuchitika ndi lalikulu, mphamvu imakhala yayikulu, mosiyana, liwiro lomwe ntchito ikuchitika ndi lochepa, mphamvu imakhala yochepa.
Mphamvu ndi kuchuluka kwa scalar. Dongosolo lapadziko lonse la mayunitsi a mphamvu ndi joule/sekondi. Joule/sekondi = watt (chidule cha W), chotchedwa polemekeza James Watt.
Dongosolo la mphamvu la Britain ndi mphamvu ya paundi imodzi-phazi pa sekondi. Gawoli ndi laling'ono kwambiri kuti ligwiritsidwe ntchito, kotero gawo lalikulu, mphamvu ya mahatchi (mwachidule hp), limagwiritsidwa ntchito. Mphamvu ya mahatchi imodzi = mphamvu ya mahatchi 550 paundi-phazi pa sekondi = ma watts 764 = ¾ kilowatt.
Kuchuluka kwa ntchito kungafotokozedwenso mu mayunitsi a mphamvu x nthawi, mwachitsanzo kilowatt-hours kapena KWH (Kilo Watt Hour). KWH imodzi ndi ntchito yochitidwa pamlingo wosasintha wa 1 kilo Watt kwa ola limodzi.
1. Munthu wolemera makilogalamu 50 amakwera makwerero okwera mamita 10 kwa mphindi ziwiri. Ngati kuthamanga chifukwa cha mphamvu yokoka (g) kuli 10 m/s2 ndiye mphamvu yopangidwa ndi...
Zokambirana
Ndizodziwika kuti :
Kulemera (m) = 50 kg
Kutalika (h) = mamita 10
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s2
Nthawi yopuma (t) = mphindi ziwiri = 2 (60) = masekondi 120
Anafunsa : mphamvu (P)
Yankhani :
Fomula ya mphamvu :
P = W / t
Kufotokozera: P = mphamvu, W = ntchito, t = nthawi
Fomula ya bizinesi :
W = F s = wh = mgh
Kufotokozera: W = ntchito, F = mphamvu, w = mphamvu yokoka, s = kusamuka, h = kutalika, m = kulemera, g = kuthamanga chifukwa cha mphamvu yokoka.
Pokwera masitepe, mphamvu yokoka imagwira ntchito pa munthu. Ntchito yochitidwa ndi mphamvu yokoka monga mphamvu yokoka imadalira kusintha kwa kutalika. Ntchito yochitidwa ndi mphamvu yokoka imapangitsa kuti mphamvu yokoka ya munthuyo iwonjezereke. Ntchito yochitidwa ndi mphamvu yokoka pa munthuyo ndi iyi:
W = mgh = (50)(10)(10) = 5000 Joules.
Kotero mphamvu yomwe imapezeka munthu akakwera masitepe ndi iyi:
P = W / t = 5000 / 120 = 41,7 Joules/sekondi.
2. Munthu wolemera makilogalamu 60 amakwera mtengo wa kokonati mpaka kutalika kwa mamita 5 m'masekondi 10. Mphamvu yofunikira kuti akwere mtengo wa kokonati ndi… g = 10 m/s2
Zokambirana
Ndizodziwika kuti :
Kulemera (m) = 60 kg
Kutalika (h) = mamita 5
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s2
Nthawi yopuma (t) = masekondi 10
Anafunsa Mphamvu
Yankhani :
Bizinesi:
W = mgh = (60)(10)(5) = 3000 Joules
Mphamvu:
P = W / t = 3000 / 10 = 300 Joules/sekondi.
