Zitsanzo 9 za Mafunso a Bizinesi
1. Mphamvu ya ma Newton 20 imagwiritsidwa ntchito pa chipika mpaka chipikacho chitasuntha mtunda wa mamita awiri. Ntchito yomwe mphamvu F imachita pa chipikacho ndi…
Zokambirana
Ndizodziwika kuti :
Mphamvu (F) = 20 N
Kusamuka (ma) = mamita awiri
Ngodya = 0 (njira ya mphamvu ndi yofanana ndi njira ya kusuntha kapena njira ya mphamvu ikugwirizana ndi njira ya kusuntha kotero kuti ngodya yopangidwa ndi mphamvu ndi kusuntha ndi zero)
Anafunsa Khama (W)
Yankhani :
Katatani:
Ngati njira ya mphamvu ndi yofanana ndi njira yosinthira, werengani ntchitoyo pogwiritsa ntchito fomula W = F s, popanda kufunikira kuwonjezera cos titi.
2. Chinthu chimakhala chosasunthika pansi. Mphamvu F = 10 N imagwiritsidwa ntchito pa chinthucho, ndikupanga ngodya ya 30o motsutsana ndi pansi. Ngati chinthucho chikuyenda mita imodzi, kodi mphamvu F imagwira ntchito yochuluka bwanji pa chinthucho?
Zokambirana
Ndizodziwika kuti :
Mphamvu (F) = 10 Newtons
Mphamvu yomwe ikupita patsogolo (F)x) = F cos 30o = (10)(0,5√3) = 5√3 Ma Newton
Kusamuka (ma) = mamita awiri
Anafunsa : khama (W) ?
Yankhani :
W = Fx s = (5√3)(1) = 5√3 Joule
3. Chinthu cholemera makilogalamu 1 chimagwa momasuka kuchokera kutalika kwa mamita awiri. Ngati kuthamanga chifukwa cha mphamvu yokoka kuli 10 m/s2, dziwani ntchito yochitidwa ndi mphamvu yokoka pa chinthucho!
Zokambirana
Ndizodziwika kuti :
Kulemera kwa chinthu (m) = 1 kg
Kutalika (h) = mamita 2
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s2
Anafunsa Ntchito yochitidwa ndi mphamvu yokoka pa chinthu (W)
Yankhani :
Njira ya mphamvu yokoka kapena kulemera (w) imapita pansi molunjika, njira ya kusuntha kwa chinthu (s) imapitanso pansi molunjika kotero kuti mphamvu yokoka ili mbali imodzi ndi njira ya kusuntha kwa chinthucho.
W = F s = wh = mgh
W = (1)(10)(2) = 20 Joule
4. Kasupe amapachikidwa ndi katundu wolemera makilogalamu 1 kotero kuti kasupeyo amakula ndi kutalika kwa masentimita 2. Ngati kuthamanga chifukwa cha mphamvu yokoka kuli 10 m/s2, dziwani (a) kasupe wokhazikika (b) ntchito yomwe kasupeyo wachita pa katundu
Zokambirana
Ndizodziwika kuti :
Kulemera (m) = 1 kg
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s2
Kuwonjezeka kwa kutalika kwa kasupe (x) = 2 cm = 0,02 mamita
Anafunsa : nthawi zonse ya masika ndi ntchito yochitidwa ndi gulu lankhondo la masika
Yankhani :
(a) Chokhazikika cha masika
Fomula ya lamulo la Hooke :
F = k x.
Sinthani fomula iyi kuti muwerengere nthawi yokhazikika ya masika:
k = F / x = w / x = mg / x
k = (1)(10) / 0,02 = 10 / 0,02
k = 500 Newton/mita
(b) Ntchito yochitidwa ndi gulu lankhondo la masika
W = – ½ kx2
W = – ½ (500)(0,02)2
W = – (250)(0,0004)
W = -0,1 Joule
Ntchito yochitidwa ndi mphamvu ya kasupe pa katundu ndi yoipa chifukwa njira ya mphamvu ya kasupe ili yosiyana ndi njira yosunthira katundu.
5. Bokosi lomwe lidakali pansi limafulumizitsidwa ndi mphamvu ya 10 N kotero kuti bokosilo lisunthe mtunda wa mamita awiri. Ngati mphamvu yokankhira ili mbali yomweyo ndi kusuntha kwa bokosilo ndipo bokosilo likugwiritsidwa ntchito ndi mphamvu ya kinetic friction ya 2 Newtons, ndiye kuti ntchito yonse yomwe yachitika pa bokosilo ndi...
Zokambirana
Ndizodziwika kuti :
Mphamvu (F) = 10 Newtons
Mphamvu ya kukangana kwa kinetic (F)k) = 2 Newton
Kusamuka (ma) = mamita awiri
Anafunsa : Khama lonse (W)okwana)
Yankhani :
Ntchito yochitidwa ndi mphamvu (F):
W1 = F s cos 0 = (10)(2)(1) = 20 Joules
Ntchito yochitidwa ndi mphamvu ya kinetic friction (F)k):
W2 =Fk s = (2)(2)(cos 180) = (2)(2)(-1) = -4 Ma Joules
Khama lonse ndi:
Wokwana =W1 - W2
Wokwana = 20-4
Wokwana = 16 Joule
6. Chinthu cholemera makilogalamu 5 chili pamtunda wa mamita 10 pamwamba pa dziko lapansi. Kuthamanga kwa mphamvu yokoka ndi 10 m/s -2 . Kuchuluka kwa ntchito yofunikira kuti chinthucho chisunthire kutalika kwa mamita 15 pamwamba pa dziko lapansi ndi...
A. . 75 Joule
B. . 250 Joule
C. . 500 Joule
D. . 750 Joule
E. 1.250 Joule
Zokambirana
Amadziwika kuti:
Kulemera kwa chinthu (m) = 5 kg
Kutalika (h) = mamita 10
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2
Funso: Kuyesetsa kusuntha chinthu kufika kutalika kwa mamita 15
Yankho:
Khama losuntha chinthu ndi lofanana ndi mphamvu yokoka yomwe imagwira ntchito pa chinthucho.
Fomula ya ntchito yochitidwa ndi mphamvu yokoka:
W = wh = mgh
Kufotokozera: W = khama, w = mphamvu yokoka, h = kutalika, m = kulemera, g = kuthamanga chifukwa cha mphamvu yokoka
Fomula ya ntchito yomwe yachitika ndi iyi:
W = wh = mgh = (5 kg)(10 m/s 2 )(10 m) = 500 kg m 2 /s 2 = 500 Joules
Yankho lolondola ndi C.
7. Chinthu cholemera makilogalamu awiri chimayenda pamalo osalala pa liwiro la 2 m/s -1 . Patapita mphindi zochepa, chinthucho chimayenda pa liwiro la 5 m/s -1 . Ntchito yochitidwa pa chinthucho panthawiyi ndi…
A. 4 Joule
B. 9 Joule
C. 15 Joule
D. 21 Joule
E. 25 Joule
Zokambirana
Amadziwika kuti:
Kulemera kwa chinthu (m) = 2 kg
Liwiro loyambirira (v o ) = 2 ms –1
Liwiro lomaliza (v t ) = 5 ms –1
Funso: Ntchito yomwe yachitika pa chinthucho panthawi yopuma
Yankho:
Chiphunzitso cha mphamvu ya work-kinetic chimanena kuti ntchito yonse yochitidwa pa chinthu ndi yofanana ndi kusintha kwa mphamvu ya kinetic ya chinthucho.
W = ΔEK = EK 2 – EK 1 = 1/2 mv t 2 – 1/2 mv o 2 = 1/2 m (v t 2 – v o 2 ) = 1/2 (2) (5 2 -2 2 ) = (1) (25-4) = 21 Joules
8. Tebulo lolemera makilogalamu 10 poyamba limagona pansi losalala, limakankhidwa kwa masekondi atatu ndipo limayenda molunjika ndi kuthamanga kwa 2 ms −2 . Kuchuluka kwa ntchito yochitidwa ndi…
A. 20 Joule
B. 30 Joule
C. 60 Joule
D. 180 Joule
E. 360 Joule
Zokambirana
Amadziwika kuti :
Kulemera (m) = 10 kg
Liwiro loyambirira (v o ) = 0 (poyamba tebulo silili lokhazikika)
Nthawi yopuma (t) = masekondi 3
Kuthamanga (a) = 2 m/s 2
Anafunsa : khama (W)?
Yankho :
Choyamba, werengani mtunda woyenda pogwiritsa ntchito fomula ya GLBB:
s = vot + ½ pa 2 = (0)(3) + ½ (2)(3) 2
s = 0 + (1)(9) = 9
Ntchito yomwe yachitika patebulo:
W = F s = (ma)(s) = (10)(2)(9) = 180 Joules
Yankho lolondola ndi D.
9. Chipika cholemera makilogalamu 1,5 chimakankhidwira mmwamba ndi mphamvu yosasintha F = 15 N pa bolodi lopendekeka monga momwe zasonyezedwera pachithunzichi. Tiyerekeze kuti kuthamanga chifukwa cha mphamvu yokoka (g) ndi 10 ms -2 ndipo kukangana pakati pa bolodi ndi bolodi lopendekeka ndi zero. Ntchito yonse yomwe yachitika pa bolodi ndi…
A. 15 J
B. 30 J
C. 35 J
D. 45 J
E. 50 J
Zokambirana
Amadziwika kuti :
Kulemera kwa chipika (m) = 1,5 kg
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2
Kulemera kwa chipika (w) = mg = (1,5)(10) = 15 Newton
Mphamvu yokakamiza (F) = 15 Newton
Funso : ntchito yonse yomwe yachitika pa boloko (W)?
Yankho :
Pali mphamvu ziwiri zomwe zikugwira ntchito pa chipikacho; mphamvu yofanana ndi kusuntha kwa chipikacho, chomwe ndi mphamvu yopondereza (F) ndi kulemera kwa chipikacho kofanana ndi pamwamba pa ndege yopendekera (w x ).
Ntchito yomwe yachitidwa ndi gulu lolimbikitsa ndi iyi:
W 1 = F s = (15 N)(2 m) = 30 N m = 30 Joules
Ntchito yochitidwa ndi gravity wx:
W 2 = w x s = (w sin 30 o )(2 m) = (15 N)(1/2)(2 m) = 15 N m = 15 Joules
Ntchito yonse yomwe yachitika pa bolodi:
Chiwerengero chonse = W 1 – W 2 = 30 J – 15 J = 15 Joules
Yankho lolondola ndi A.
