1. Imoto enesisindo esingama-5000 kg isheshiswe ukusuka ekuphumuleni iye kuma-20 m/s. Nquma umsebenzi ophelele owenziwe emotweni.
Kwaziwa:
Isisindo (m) = 5000 kg
Isivinini sokuqala (v o ) = 0 m/s ( ukuphumula kwemoto )
Isivinini sokugcina (v t ) = 20 m/s
Okufunwayo : inethiwekhi
Isixazululo:
Umgomo wamandla okusebenza-kinetic :
I-W inethi = Δ EK
W inetha = ½ m (v t 2 – v o 2 )
I-W inethi = umsebenzi wenethi
Δ EK = ushintsho lwamandla e-kinetic
m = isisindo (kg),
v t = isivinini sokugcina (m/s),
v o = isivinini sokuqala (m/s).
Inethiwekhi:
W inetha = ½ m (v t 2 – v o 2 )
W inetha = ½ (5000)(20 2 – 0 2 )
I-W inethi = (2500)(400 - 0)
I-W inethi = (2500)(400)
I-W inethi = 1000,000 Joule
2. Into enesisindo esingu-10 kg isheshiswe kusuka ku-5 m/s kuya ku-10 m/s. Nquma umsebenzi wenethi owenziwe entweni!
Kwaziwa:
Isisindo (m) = 10 kg
Isivinini sokuqala (v o ) = 5 m/s
Isivinini sokugcina (v t ) = 10 m/s
Okufunwayo : inethiwekhi
Isixazululo:
Inethiwekhi:
I-W inethi = Δ EK
W inetha = ½ m (v t 2 – v o 2 )
W inetha = ½ (10)(10 2 – 5 2 )
I-W inethi = (5)(100 - 25)
I-W inethi = (5)(75)
I-W inethi = 375 Joule
3. Imoto enesisindo esingama-2000 kg yehla ngesivinini kusuka ku-10 m/s kuya ku-5 m/s. Yimuphi umsebenzi owenziwayo emotweni?
Kwaziwa:
Isisindo semoto (m) = 2000 kg
Isivinini sokuqala (v o ) = 10 m/s
Isivinini sokugcina (v t ) = 5 m/s
Okufunwayo: inethiwekhi
Isixazululo:
Inethiwekhi:
I-W inethi = Δ EK
W inetha = ½ m (v t 2 – v o 2 )
W inetha = ½ (2000)(5 2 – 10 2 )
I-W inethi = (1000)(25 - 100)
I-W inethi = (1000)(-75)
I-W inetha = -75,000 amaJoule
Uphawu lokususa lubonisa ukuthi indlela yokufuduka iphambene nendlela yamandla e-net.
4. Amandla angaguquki angu-60-N asetshenziswa entweni engu-10-kg imizuzwana eyi-12. Ijubane lokuqala lento lingu-6 m/s futhi isiqondiso sento sifana nesiqondiso samandla.
(1) Umsebenzi owenziwe kule nto ungama-Joules angu-30,240
(2) Amandla okugcina e-kinetic angama-30,240 joules
(3) Amandla angama-2,520 Watt
(4) Ukwanda kwamandla e-kinetic ento kungama-Joules ayi-180
Izitatimende eziqondile zithi…
Kwaziwa:
Amandla (F) = 60 N
Isikhawu sesikhathi (t) = imizuzwana eyi-12
Isisindo sento (m) = 10 kg
Ijubane lokuqala (v o ) = 6 m/s
Okufunwayo: Izitatimende ezifanele
Isixazululo:
Ukusheshisa kwento:
∑F = ma
60 = 10 a
a = 60 / 10 = 6 m/s 2
Ijubane lokugcina:
v t = vo o + at
v t = 6 + (6)(12)
v t = 6 + 72
v t = 78 m/s
Ibanga elihanjiwe ngemizuzwana eyi-12 :
s = vot + 1/2 ku- 2
s = (6)(12) + 1/2 (6)(12) 2
s = 72 + (3)(144)
s = 72 + 432
s = amamitha ayi-504
(1) Umsebenzi owenziwe ngenkani
W = F s = (60)(504) = 30,240 amaJoules
(2) Amandla okugcina e-kinetic
KE = 1/2 mv t 2 = 1/2 (10) (78) 2 = (5) (6084) = 30,420 Joules
(3) Amandla
P = W / t = 30,240 / 12 = 2,520 amaJoules/isekhondi
(4) Ukwanda kwamandla e-kinetic
ΔKE = 1/2 mv t 2 – 1/2 mv o 2 = 1/2 m (v t 2 – v o 2 ) = 1/2 (10)(78 2 – 6 2 ) = 5 (6084 –36) = 5 (6048)
I-ΔKE = 30,240 amaJoule
5. Umsebenzi omkhulu wenziwa ngenombolo yento…

Isixazululo:
Umsebenzi we-Net = ushintsho lwamandla e-kinetic
W inetha = ½ m (v t 2 – v o 2 )
Umsebenzi omkhulu:
W 1 = ½ (8)(4 2 – 2 2 ) = (4)(16 – 4) = (4)(12) = 48 Ama-Joules
W 2 = ½ (8)(5 2 –3 2 ) = (4)(25 – 9) = (4)(16) = 64 Ama-Joules
W 3 = ½ (10)(6 2 – 5 2 ) = (5)(36 – 25) = (5)(11) = 55 Ama-Joules
W 4 = ½ (10)(4 2 – 0 2 ) = (5)(16 – 0) = (5)(16) = 80 Ama-Joules
W 5 = ½ (20)(3 2 – 3 2 ) = (10)(9 – 9) = (10)(0) = 0 Ama-Joules
6. Imoto enesisindo esingamakhilogremu angu-4000 ihamba ngomugqa oqondile ngesivinini esingama-25 m/s. Imoto yehliswa ukuze ijubane lokugcina lemoto libe ngu-15 m/s. Uyini umsebenzi owenziwe emotweni?
Kwaziwa:
Isisindo (m) = 4000 kg
Ijubane lokuqala (v o ) = 25 m/s
Ijubane lokugcina (v t ) = 15 m/s
Okufunwayo : Umsebenzi owenziwe emotweni
Isixazululo:
I-W inethi = ½ m (v t 2 – vo 2 ) = ½(4000)(15 2 -25 2 ) = (2000)(225-625) = (2000)(-400) = -800,000 Ama-Joules = -800 kJ
7. I-0.1-kg ephonswe ngokuvundlile ku-6 m/s ukusuka ekuphakameni kwamamitha ama-5. Uma ukusheshisa kwamandla adonsela phansi kungu-10 m/s 2 , khona-ke iyini amandla e-kinetic ebhola ekuphakameni kwamamitha ama-2.
Kwaziwa:
Isisindo (m) = 0.1 kg
Ushintsho lokuphakama (h) = 5 m – 2 m = 3 amamitha
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Okufunwayo: Amandla e-kinetic ekuphakameni kwamamitha amabili.
Isixazululo:
Ukunyakaza okubonakalayo kungaqondwa ngokuhlaziya izingxenye ezivundlile neziqondile zokunyakaza ngokwehlukana. Ukunyakaza okuvundlile kuhlaziywe njengokunyakaza kwejubane okungaguquki kanye nokunyakaza okuvundlile kuhlaziywe njengokunyakaza kokuwa kwamahhala noma ukunyakaza okuvundlile.
Amandla okuqala omshini = amandla adonsela phansi anamandla adonsela phansi.
I-PE = mgh = (0.1)(10)(3) = 3 amaJoules.
Amandla okugcina omshini = amandla e-kinetic.
KE = 3 amaJoules.
8. Imoto enesisindo esingamakhilogremu ayi-1000 ishesha kakhulu uma iphumula futhi ihamba ngesivinini esingama-5 m/s. Uyini umsebenzi owenziwa yimoto?
Kwaziwa:
Isisindo (m) = 1000 kg
Ijubane lokuqala (v o ) = 0
Ijubane lokugcina (v t ) = 5 m/s
Okufunwayo: Umsebenzi (W) owenziwa ngemoto
Isixazululo:
W inetha = ½ m (v t 2 – v o 2 )
Umsebenzi owenziwe ngemoto:
I-W inethi = ½ (1000)(5 2 – 0 2 ) = (500)(25 – 0) = (500)(25) = 12,500 amaJoules
9. Ibhola elingamagremu angu-500 liphonswa phezulu phezulu lisuka ebusweni bomhlaba ngesivinini sokuqala esingu-10 m/s 2 . Ukusheshisa ngenxa yamandla adonsela phansi kungu-10 ms -2 . Uyini umsebenzi owenziwa amandla esisindo lapho ibhola lifinyelela ukuphakama okuphezulu.
Kwaziwa :
Isisindo sebhola (m) = amagremu angu-500 = 0.5 kg
Ijubane lokuqala (v o ) = 10 m/s 2
Ijubane lokugcina (v t ) = 0 (ijubane endaweni ephezulu kakhulu)
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Okufunwayo: Umsebenzi (W) don ngesisindo
Isixazululo:
Umsebenzi we-net owenziwe ngamandla e-net entweni = ushintsho kumandla e-kinetic.
I-W inethi = ΔEK = EK t – EK o
I-Wnet = ½ mv t 2 – ½ mv o 2 = ½ m (v t 2 – v o 2 )
I-KE t = amandla okugcina e-kinetic, i-KE o = amandla okuqala e-kinetic, m = isisindo sento, v t = ijubane lokugcina lento, v o = ijubane lokuqala lento.
Inethiwekhi:
W inetha = ½ m (v t 2 – v o 2 ) = ½ (0.5)(0 2 – 10 2 )
I-W inethi = (0.25)(-100) = -25 Ama-Joule
Uphawu lokususa lubonisa ukuthi indlela yokugudluka iphambene nesisindo sebhola. Indlela ibhola elibheke ngayo iqondile kanti indlela yesisindo iqondile.
10. Into enesisindo esingu-1 kg iyawa ngomehluko wokuphakama = amamitha angu-2.5. Ukusheshisa ngenxa yamandla adonsela phansi kungu-10 ms -2 . Uyini umsebenzi owenziwayo entweni?
Kwaziwa:
Isisindo sebhola (m) = 1 kg
Ijubane lokuqala (v o ) = 0 m/s
Ukuphakama (h) = amamitha angu-2.5
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Okufunwayo: Umsebenzi we-inthanethi ngesikhathi sokufuduka
Isixazululo:
Ijubane lokugcina lebhola (v t )
Kubalwa kusetshenziswa i-equation yokunyakaza kokuwa okukhululekile. Okuyaziwayo: Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2 , Ushintsho ekuphakameni kwebhola (h) = amamitha angu-2.5. Okufunwayo: Ijubane lokugcina.
v t 2 = 2 gh = 2(10)(2.5) = 2(25)
v t = √2(25)
v t = 5√2
Umsebenzi we-Net = ushintsho lwamandla e-kinetic
W inetha = ΔEK = ½ m (v t 2 – v o 2 ) = ½ (1){(5√2) 2 – 0 2 }
I-W inethi = ½ (25)(2) = 25 amaJoule
11. Into engamakhilogremu angu-2 ihamba ngesivinini esingamakhilomitha angu-72 ngehora. Ngemva kokuhamba amamitha angu-400, ijubane lokugcina lento lingu-144 km ngehora. Ukusheshisa ngenxa yamandla adonsela phansi kungu-10 ms -2 . Thola umsebenzi wenethi.
Kwaziwa:
Isisindo sento (m) = 2 kg
Ijubane lokuqala (v o ) = 72 km/ihora = 20 m/s
Ijubane lokugcina (v t ) = 144 km/h = 40 m/s
Ibanga (ama) = amamitha angu-400
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 m/s 2
Okufunwayo: Inethiwekhi
Isixazululo:
Umsebenzi we-net = izinguquko zamandla e-kinetic
W inetha = ΔEK = ½ m (v t 2 – v o 2 ) = ½ (2)(40 2 – 20 2 }
I-W inetha = ½ (2)(1600 - 400) = 1200 amaJoules
12. Into engamakhilogremu angu-2 ihamba ngesivinini esingu-2 ms –1 . Umsebenzi owenziwe entweni ungama-Joules angu-21. Iyini ijubane lokugcina lento.
Kwaziwa:
Isisindo (m) = 2 kg
Ijubane lokuqala (v o ) = 2 m/s
Umsebenzi (W) = 21 Joule
Okufunwayo: ijubane lokugcina (v t )
Isixazululo:
I-W inethi = ΔEK
I-W inethi = 1/2 mv t 2 -1/2 mv o 2
I-W inetha = 1/2 m (v t 2 – v o 2 )
21 = 1/2 (2) (v t 2 – 2 2 )
21 = (v t 2 – 2 2 )
21 = v t 2 – 4
v t 2 = 21 + 4 = 25
v t = √25
v t = 5 m/s
1 3. Amandla angaguquki angu-8 N asebenza entweni enesisindo esingu-16 kg. Uma into iqale iphumule, khona-ke nquma ijubane lento ngemva kokuba amandla esebenza entweni imizuzwana emi-4.
Kwaziwa:
Amandla angaguquki (F) = 8 Newton
Isisindo sento (m) = 16 kg
Isivinini sokuqala sento (v o ) = 0 m/s
Isikhawu sesikhathi amandla asebenza entweni (t) = imizuzwana emi-4
Okufunwayo: Isivinini sokugcina (v t )
Isixazululo:
Umsebenzi = Ushintsho emandleni e-kinetic
W = KE final – KE initial
W = ½ mv t 2 – ½ mv o 2
W = ½ mv t 2 – 0
W = ½ mv t 2 —— Isibalo 1
Umsebenzi = Amandla x Ukufuduka
W = F d
W = 8 d
Sebenzisa i-equation yokunyakaza okuqondile okungalingani ngezansi ukuze ubale ukufuduka (d):
d = vot + ½ ku- 2
d = ukufuduka, v o = ijubane lokuqala, t = isikhawu sesikhathi, a = ukusheshisa
d = 0 + ½ ku- 2 = ½ ku- 2 —-> a = (v t – vo o ) / t = v t / t
d = ½ (v t / t) t 2
d = ½ (v t ) t
Shintsha ukufuduka (d) ku-equation ethi Umsebenzi ngokufuduka (d) kulesi sibalo:
W = 8 d
W = 8(1/2)(v t )(t)
W = (4)(v t )(t) —— isibalo 2
Isibalo 1 = Isibalo 2
W = W
½ mv t 2 = (4)(v t )(t)
½ mv t = (4)(t)
½ (16)(v t ) = 4(4)
8 v t = 16
v t = 16/8
v t = 2 amamitha/umzuzwana
14. Ukuze wandise ijubane lento ibe izikhathi ezimbili zejubane lokuqala, nquma umsebenzi odingekayo enkambisweni…
Kwaziwa:
Isisindo sento (m) = 1 kg
Isivinini sokuqala (v o ) = 1 m/s
Isivinini sokugcina (v t ) = 2 x isivinini sokuqala = 2 x 1 = 2 m/s
Okufunwayo: Umsebenzi
Isixazululo:
Amandla okuqala e-kinetic:
KE isiqalo = ½ mv o 2 = ½ (1)(1) 2 = ½ (1)(1) = ½ (1) = 0.5
Amandla okugcina e-kinetic lapho ijubane lento liba kabili kunejubane layo lokuqala:
KUYA kokugcina = ½ mv t 2 = ½ (1)(2) 2 = ½ (4) = 2
Ithiyori yamandla okusebenza-kinetic:
Umsebenzi = Ushintsho lwamandla e-kinetic
Umsebenzi = Amandla okugcina e-kinetic – amandla okuqala e-kinetic
Umsebenzi = 2 – 0.5
Umsebenzi = 1.5
Amandla okuqala e-kinetic = 0.5
Umsebenzi = 3 x 0.5 = 1.5
Umsebenzi odingekayo izikhathi ezintathu zamandla ayo okuqala e-kinetic.
15. Imoto enesisindo esingu-1500 kg ihamba ngesivinini esingu-36 km/ihora emgwaqweni oqondile nobushelelezi ovundlile. Imoto isheshise yafika ku-72 km/ihora. Thola umsebenzi odingekayo ukuze imoto isheshise.
Kwaziwa:
Isisindo semoto (m) = 1500 kg
Isivinini sokuqala semoto (v o ) = 36 km/ihora = 36,000 amamitha / 3600 isekhondi = 10 amamitha/isekhondi
Isivinini sokugcina semoto (v t ) = 72 km/ihora = 72,000 amamitha / 3600 imizuzwana = 20 amamitha/isekhondi
Kufunwa: Kudingeka umsebenzi ukuze kusheshiswe imoto
Isixazululo:
Ithiyori yamandla okusebenza-kinetic:
W = EK final – isiqalo se-EK
W = ½ mv t 2 – ½ mv o 2 = ½ m (v t 2 –v o 2 )
W = ½ (1500)(20 2 – 10 2 )
W = ½ (1500)(400 - 100)
W = ½ (1500)(300)
W = (1500)(150)
W = amaJoules angu-225,000
16. Into enesisindo esingu-2 kg iqala ukuhamba ngesivinini esingu-72 km. ihora -1 . Ngemva kokuhamba emgwaqweni oqondile ovundlile kuze kufike ku-400 m, ijubane lento lingu-144 km . ihora -1 . Thola umsebenzi ophelele entweni.
Kwaziwa:
Isisindo sento (m) = 2 kg
Isivinini sokuqala (v o ) = 72 km/ihora = 72,000 amamitha / 3600 imizuzwana = 20 m/s
Isivinini sokugcina (v t ) = 144 km/ihora = 144,000 amamitha / 3600 imizuzwana = 40 m/s
Ukufuduka kwento = amamitha angu-400
Okufunwayo: Umsebenzi we-inthanethi entweni
Isixazululo:
Ithiyori yamandla okusebenza-kinetic ithi umsebenzi wenethi usebenza entweni ngendlela efanayo nokushintsha kwamandla okusebenza kwento.
I-W inethi = IYA kokugcina – IYA kokuqala
I-W inethi = ½ mv t 2 – ½ mv o 2
W inetha = ½ m (v t 2 – v o 2 )
W inetha = ½ (2)(40 2 – 20 2 )
I-W inethi = 1600 – 400
I-W inethi = 1200 Joule
incazelo:
W = Umsebenzi, KE = amandla e-kinetic
Amandla weKinetic
17. Inhlamvu engamagremu ayi-10 ehamba ngesivinini esingaguquki esingu-100 m/s. Iyini amandla e-kinetic enhlamvu.
Kwaziwa:
Isisindo senhlamvu (m) = amagremu ayi-10 = 10/1000 amakhilogremu = 1/100 amakhilogremu = 0.01 amakhilogremu
Isivinini senhlamvu (v) = amamitha ayi-100/umzuzwana
Okufunwayo: Amandla e-Kinetic
Isixazululo:
I-KE = 1/2 mv 2
I-KE = 1/2 (0,01 kg)(100 m/s) 2
KE = 1/2 (0,01 kg)(10.000 m 2 /s 2 )
KE = (0,01 kg)(5000 m 2 /s 2 )
KE = 50 kg m 2 /s 2
KE = 50 amaJoule
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