1. Munthu amakoka chipika cha mamita awiri pamwamba pa malo opingasa ndi mphamvu yosasintha F = 20 N. Dziwani ntchito yochitidwa ndi mphamvu F ikugwira ntchito pa chipikacho.
Zodziwika:
Mphamvu (F) = 20 N
Kusamuka (s) = 2 m
Ngodya (θ ) = 0
Akufuna : Ntchito (W)
Yankho:
W = F d cos θ = (20) (2) (cos 0) = (20) (2) (1) = 40 Joules
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2. Mphamvu F = 10 N ikugwira ntchito pa bokosi la 1 m motsatira malo opingasa. Mphamvu imagwira ntchito pa ngodya ya 30 o monga momwe chithunzi chili pansipa chikusonyezera. Dziwani ntchito yochitidwa ndi mphamvu F!
Zodziwika :
Mphamvu (F) = 10 N
Mphamvu yopingasa (F x ) = F cos 30 o = (10)(0.5√3) = 5√3 N
Kusamuka (d) = mita imodzi
Akufuna : Ntchito (W)?
Yankho :
W = F x d = (5√3)(1) = 5√3 Ma Joule
3. Thupi limagwa momasuka kuchokera pamalo opumula, kuchokera kutalika kwa mamita awiri. Ngati kuthamanga chifukwa cha mphamvu yokoka kuli 10 m/s 2 , dziwani ntchito yomwe yachitika ndi mphamvu yokoka!
Zodziwika:
Kulemera kwa chinthu (m) = 1 kg
Kutalika (h) = 2 m
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2
Kufunidwa: Ntchito yochitidwa ndi mphamvu yokoka (W)
Yankho:
W = F d = wh = mgh
W = (1)(10)(2) = 20 Joule
W = ntchito, F = mphamvu, d = mtunda, w = kulemera , h = kutalika, m = kulemera, g = kuthamanga chifukwa cha mphamvu yokoka.
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4. Chinthu cholemera makilogalamu 1 chimalumikizidwa ku kasupe kotero kuti chimatalika masentimita 2. Ngati kuthamanga chifukwa cha mphamvu yokoka kuli 10 m/s 2 , dziwani (a) kasupe wokhazikika (b) ntchito yochitidwa ndi mphamvu ya kasupe pa chinthucho
Zodziwika:
Kulemera (m) = 1 kg
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2
Kutalika (x) = 2 cm = 0.02 m
Kulemera (w) = mg = (1 kg)(10 m/s 2 ) = 10 kg m/s 2 = 10 N
Kufunidwa: Nthawi yokhazikika ya masika ndi ntchito yochitidwa ndi mphamvu ya masika
Yankho:
(a) Chokhazikika cha masika
Fomula ya lamulo la Hooke :
F = k x.
k = F / x = w / x = mg / x
k = (1)(10) / 0.02 = 10 / 0.02
k = 500 N/m
(b) ntchito yochitidwa ndi mphamvu ya masika
W = – ½ kx 2
W = – ½ (500)(0.02) 2
W = – (250)(0.0004)
W = -0.1 Joule
Chizindikiro chochotsera chimasonyeza kuti mphamvu ya kasupe ikupita mosiyana ndi komwe chinthu chikusuntha.
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5. Mphamvu F = 10 N imafulumizitsa bokosi pamwamba pa kusuntha kwa 2 m. Pansi pake ndi lolimba ndipo limagwiritsa ntchito mphamvu yokangana F k = 2 N. Dziwani ntchito yolumikizidwa pa bokosilo.
Zodziwika:
Mphamvu (F) = 10 N
Mphamvu ya kukangana kwa kinetic (F k ) = 2 N
Kusamuka (d) = 2 m
Akufuna: Network (W net )
Yankho:
Ntchito yochitidwa ndi mphamvu F:
W 1 = F d cos 0 = (10)(2)(1) = 20 Joules
Ntchito yochitidwa ndi mphamvu ya kupsinjika kwa kinetic (F k ):
W 2 = F k d = (2)(2)(cos 180) = (2)(2)(-1) = -4 Ma Joules
Netiweki:
W net = W 1 – W 2
W net = 20 – 4
W net = 16 Joule
6. Kodi ntchito yochitidwa ndi mphamvu F pa boloko ndi yotani?
Zodziwika:
Mphamvu (F) = 12 Newton
Kusamuka (d) = mamita 4
Akufuna: Ntchito (W)
Yankho:
W = F d = (12 Newton)(mamita 4) = 48 N m = 48 Joules
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7. Block imakankhidwa ndi mphamvu ya 200 N. Kusuntha kwa block ndi mamita awiri. Kodi ntchito yotani yomwe imachitika pa block ndi yotani?
Zodziwika:
Mphamvu (F) = 200 Newton
Kusamuka (d) = mamita 2
Akufuna: Ntchito (W)
Yankho:
Ntchito:
W = F s
W = (200 Newton)(mamita awiri)
W = 400 N m
W = 400 Joule
8. Dalaivala wa galimoto ya sedan akufuna kuyimitsa galimoto yake pa mtunda wa mamita 0.5 kutsogolo kwa galimoto yomwe ili pamtunda wa mamita 10 kuchokera pamalo a galimoto ya sedan. Kodi galimoto ya sedan imafunika ntchito yotani?
Zodziwika:
Kusamuka (d) = mamita 10 – mamita 0.5 = mamita 9.5
Mphamvu (F) = 50 Newton
Akufuna: Ntchito (W)
Yankho:
W = F s
W = (50 Newton)(mamita awiri)
W = 475 N m
W = 475 Joule
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9.
Ntchito yochitidwa ndi Tom ndi Jerry kuti galimotoyo iyende mpaka mamita 4. Mphamvu zomwe Tom ndi Jerry amagwiritsa ntchito ndi 50 N ndi 70 N.
Zodziwika:
Kusamuka (ma) = mamita 4
Mphamvu ya Neti (F) = 50 Newtons + 70 Newtons = 120 Newtons
Akufuna: Ntchito (W)
Yankho:
W = F s = (120 Newton)(mamita 4) = 480 N m = 480 Joules
10. Dalaivala akukoka galimoto kuti galimotoyo iyende mpaka 1000 cm. Kodi ntchito yotani yomwe yachitika pa galimotoyo ndi yotani?
Zodziwika:
Mphamvu (F) = 250 Newton
Malo osamukira = 1000 cm = 1000/100 mamita = 10 mamita
Akufuna: Ntchito (W)
Yankho:
W = F s = (250 Newton)(mamita 10) = 2500 N m = 2500 Joules
11. Kutengera chithunzi chomwe chili pansipa, ngati ntchito yochitidwa ndi mphamvu ya neti ndi 375 Joules, dziwani kusamuka kwa chinthucho.
Zodziwika:
Ntchito (W) = 375 Joule
Mphamvu zonse ( ΣF) = 40 N + 10 N – 25 N = 25 Newtons ( kumanja )
Kufunidwa: Kusamutsidwa ( d )
Yankho:
Chiyerekezo cha ntchito:
W = F s
Kusamutsa kwa chinthu:
d = W / F = 375 Joules / 25 Newtons
d = mamita 15 s
12. Zochita zomwe zili pansipa sizigwira ntchito ndi ...
A. Kankhirani chinthu mpaka mamita 10
B. Kankhirani galimoto mpaka itayenda
C. Kankhani khoma
D. Ndinakoka bokosi
Yankho:
Chiyerekezo cha ntchito:
W = ΣF s
W = ntchito , F = mphamvu , d = kusamuka
Kutengera ndi njira yomwe ili pamwambapa, ntchito imachitika ndi mphamvu ndipo pali kusamuka.
Yankho lolondola ndi C.
1 3. Andrew akukankha chinthu ndi mphamvu ya 20 N kotero kuti chinthucho chimayenda mozungulira ndi utali wa mamita 7. Dziwani ntchito yomwe Andrew wachita pozungulira kawiri.
A. 0 Joule
B. 1400 Joule
C. 1540 Joule
D. 1760 Joule
Yankho:
Ngati munthuyo akankhira mpando wa olumala kawiri, ndiye kuti munthuyo ndi mpando wa olumala amabwerera pamalo ake oyamba, kotero kusamuka kwa munthuyo ndi zero.
Kusamuka = 0 kotero ntchito = 0.
Yankho lolondola ndi A.
14. Winawake akukankhira chinthu pansi ndi mphamvu ya 350 N. Pansi pake pali mphamvu yokangana ya 70 N. Dziwani ntchito yochitidwa ndi mphamvu kuti chinthucho chisunthire kutali mamita 6.
A. 45 J
B. 72 J
C. 1680 J
D. 2580 J
Zodziwika:
Mphamvu ya kukankhira (F) = 350 Newtons
Mphamvu yokangana (F fric ) = 70 Newtons
Kusamutsidwa kwa chinthu (s) = mamita 6
Akufuna: Ntchito (W)
Yankho:
Pali mphamvu ziwiri zomwe zimagwira ntchito pa chinthucho, mphamvu yokakamiza (F) ndi mphamvu yokakamiza (F fric ). Mphamvu yokakamiza ili ndi njira yofanana ndi kusuntha kwa chinthucho chifukwa mphamvu yokakamiza imagwira ntchito yabwino. M'dzanja lina, mphamvu yokakamiza ili ndi njira yosiyana ndi kusuntha kwa chinthucho kotero kuti mphamvu yokakamiza imagwira ntchito yolakwika.
Ntchito yochitidwa ndi mphamvu yokakamiza:
W = F d = (350 Newton)(mamita 6) = 2100 Newton-mita = 2100 Joules
Ntchito yochitidwa ndi mphamvu yolimbana:
W = – (F fric )(s) = – (70 Newton)(mamita 6) = – 420 Newton-mita = – 420 Joules
Netiweki:
W net = 2100 Joules – 420 Joules
W net = 1680 Joule
Yankho lolondola ndi C.
15. Chinthu chimakankhidwa ndi mphamvu yopingasa ya ma Newton 14 pansi yosasunthika ndi mphamvu yokangana ya ma Newton 10. Dziwani ntchito yoyendera chinthucho mpaka mamita 8.
A. 0.5 Joule
B. 3 Joule
C. 32 Joule
D. 192 Joule
Zodziwika:
Mphamvu yokankhira (F) = 14 Newton
Mphamvu yokangana (F fric ) = 10 Newtons
Kusamutsidwa kwa chinthu (d) = mamita 8
Akufuna: Ntchito (W)
Yankho:
Pali mphamvu ziwiri zomwe zimagwira ntchito pa chinthu, mphamvu yokakamiza (F) ndi mphamvu yokangana (F fric ).
Mphamvu yokankhira ili ndi mbali yofanana ndi kusuntha kwa chinthu kotero kuti mphamvu yokankhira imagwira ntchito yabwino. Kumbali ina, mphamvu yokankhira ili ndi mbali yosiyana ndi kusuntha kwa chinthu kotero kuti mphamvu yokankhira imagwira ntchito yoipa.
Ntchito yochitidwa ndi mphamvu yokakamiza:
W = F s = (14 Newton)(mamita 8) = 112 Newton mamita = 112 Joules
Ntchito yochitidwa ndi mphamvu yolimbana:
W = – (F fric )(s) = – (10 Newton)(mamita 8) = – 80 Newton mamita = – 80 Joules
Netiweki:
W net = 112 Joules – 80 Joules
W net = 32 Joule
Yankho lolondola ndi C.
16. Dziwani ntchito ya ukonde kutengera chithunzi chomwe chili pansipa.
A. 360 Joule
B. 450 Joule
C. 600 Joule
D. 750 Joule
Yankho:
Ntchito = Mphamvu (F) x kusamuka (d)
Ntchito = Malo a katatu 1 + dera la rectangle + dera la katatu 2
Work = 1/2(40-0)(3-0) + (40-0)(9-3) + 1/2(40-0)(12-9)
Ntchito = 1/2(40)(3) + (40)(6) + 1/2(40)(3)
Ntchito = (20)(3) + 240 + (20)(3)
Ntchito = 60 + 240 + 60
Ntchito = 360 Joule
Yankho lolondola ndi A.
17. Chidutswa cha matabwa chotalika masentimita 60 chimalumikizidwa pansi molunjika. Matabwa amamenyedwa ndi nyundo ya makilogalamu 10 kuchokera kutalika kwa masentimita 40 pamwamba pa matabwa. Ngati mphamvu yolimbana ndi nthaka ndi 2 x 10 3 N ndipo kuthamanga chifukwa cha mphamvu yokoka ndi 10 m/s 2 , ndiye kuti matabwawo amalowa pansi kwathunthu akangogunda.
A. 4
B. 16
C. 28
D. 30
Zodziwika:
Kulemera kwa nyundo (m) = 10 kg
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/ s 2
Kulemera kwa nyundo (w) = mg = (10)(10) = 100 kg m/s 2
Kusuntha nyundo musanagunde matabwa (d) = 40 cm = 0.4 metres
Kukana kwa matabwa (F) = 2 x 10 3 N = 2000 N
Kutalika kwa matabwa = 60 cm = 0.6 metres
Akufuna: Matabwa adzalowa pansi kwathunthu… akagunda.
Yankho:
Ntchito yochitidwa pa nyundo ikayenda mpaka mamita 0.4 ndi:
W = F d = ws = (100 N)(0.4 m) = 40 Nm = 40 Joules
Ntchito yochitidwa ndi mphamvu yotsutsa ya pansi:
W = F d = (2000 N)(0.6 m) = 1200 Nm = 1200 Joules
Matabwa adzalowa pansi kwathunthu… akagunda.
Ma Joules 1200 / Ma Joules 40 = 30
Yankho lolondola ndi D.
[wpdm_package id='1192′]
- Ntchito yochitidwa ndi mphamvu ndi mavuto ndi mayankho
- Mavuto ndi mayankho a mphamvu zogwirira ntchito
- Mavuto ndi mayankho a mfundo za mphamvu za makina ndi ntchito
- Mavuto ndi mayankho a mphamvu yokoka
- Mphamvu yomwe ingagwiritsidwe ntchito pa mavuto ndi mayankho a masika otanuka
- Mavuto amagetsi ndi mayankho
- Kugwiritsa ntchito mphamvu yamakina yosungira kuti munthu agwe momasuka
- Kugwiritsa ntchito mphamvu yamakina yosungira kayendedwe ka mmwamba ndi pansi mu kayendedwe ka free fall
- Kugwiritsa ntchito kusunga mphamvu yamakina kuti iyende pamwamba pa curve
- Kugwiritsa ntchito mphamvu yamakina yosungira kuti munthu ayende pa ndege yopendekeka
- Kugwiritsa ntchito mphamvu ya makina yosungira kuti zigwiritsidwe ntchito poyendetsa zinthu
