4 Mehlala ea mosebetsi le matla a khoheli a ka bang teng
1. Ntho e boima ba 1 kg hoetla mahala ho tloha bophahamong ba limithara tse 10 ho ea holimo ho lefatše. Fumana:
(a) Mosebetsi o entsoeng ke matla a khoheli holim'a ntho eo
(b) Liphetoho matla a ka bang teng matla a khoheli
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s2
Puisano
Hoa tsebahala :
Boima ba ntho (m) = 1 kg
Bophahamo (h) = limithara tse 10
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s2
Karabo:
(a) Mosebetsi o etsoang ka matla a khoheli
Ha ntho e wela ka bolokolohi, tataiso ya motsamao wa ntho e ya tlase mme tataiso ya matla a kgohedi a sebetsang hodima ntho (boima ba ntho) le yona e ya tlase. Hobane a le ka lehlakoreng le le leng, matla a kgohedi a tsamaellana kapa a etsa sekhutlo sa 0o ka tataiso ea motsamao oa ntho. Cos 0 = 1 'me nomoro e' ngoe le e 'ngoe e atisitsoeng ka 1 e tšoana le nomoro eo, kahoo cos 0 ha e hloke ho kenyelletsoa foromong ea mosebetsi.
Foromo ea mosebetsi ke W = F s, moo W = mosebetsi, F = matla le s = ho falla. Haeba e fetotsoe ho latela bothata bona, foromo ea mosebetsi e fetoha ho W = wh = mgh, moo W = mosebetsi, w = matla a khoheli, h = phetoho bophahamong ba ntho, m = boima ba ntho, g = ho potlaka ka lebaka la matla a khoheli.
Kahoo mosebetsi o etsoang ke matla a khoheli ke:
W = wh = mgh = (1)(10)(10) = 100 Joule
(B) Phetoho ea matla a khoheli
Bophahamong ba limithara tse 10 ka holim'a mobu, matla a khoheli a ntho ke li-Joules tse 100. Ha e ntse e theohela tlase, bophahamo ba ntho boa fokotseha, kahoo e fokotsa matla a eona a khoheli. Ha e fihla fatše, moo bophahamo ba ntho e leng lefela, matla a eona a khoheli a ke lefela. Ka hona, matla a khoheli a ntho a fokotseha ka li-Joules tse 100.
2. Ntho e boima ba di-Newton tse 10 e sebakeng se bataletseng se sekametseng ka sekhutlo sa tshekamelo sa 30°.oBolelele ba hypotenuse ke limithara tse 2. Mosebetsi o etsoang ke matla a khoheli nthong ha e ntse e thella ho theosa le hypotenuse ke…
Puisano
Hoa tsebahala :
Matla a khoheli (w) = 10 Newton
wx = sebe tit = (10)(sebe sa 30o) = (10)(0,5) = 5 Newton
Bolelele ba hypotenuse (s) = limithara tse 2
Ho potlaka ka lebaka la matla a khoheli (g) = 10 m/s2
E botsitsoe : mosebetsi o entsoeng ke matla a khoheli
Jawab :
Bothata bona bo ka rarolloa ka litsela tse peli.
Tsela ea pele :
Foromo ea mosebetsi ke W = F s. Haeba e fetotsoe ho latela bothata bona, foromo ea mosebetsi e fetoha ho W = wx s. Kahoo mosebetsi o etsoang ke matla a khoheli ke W = wx s = (5)(2) = 10 Dijoule.
Tsela ea bobeli :
Mosebetsi o etsoang ke matla a bolokang lintho, joalo ka matla a khoheli, ha o itšetlehe ka tsela eo ntho e e nkang empa o itšetlehile ka phetoho ea bophahamo. Ka hona, ho bala mosebetsi o entsoeng ke matla a khoheli, qala ka ho bala bophahamo ba ntho.
Sebe sa 30o = lehlakore le otlolohileng / hypotenuse
0,5 = lehlakore le otlolohileng / 2
Lehlakore le otlolohileng = (0,5)(2)
Lehlakore le otlolohileng = mithara e le 1
Bophahamo ba ntho eo ke mithara e le 'ngoe.
Mosebetsi o etsoang ke matla a khoheli ha ntho e theohela tlase ke W = wh = (10)(1) = 10 Joules.
3. Matla a dijoule tse 5000 a sebediswa ho phahamisa ntho e boima ba 50 kg. Ntho eo e tla nyolohela bophahamong ba… g = 10 m/s2
A. 5 m
B. 10 m
C. 12 m
D. 15 m
E. 20 m
Puisano:
Hoa tsebahala :
Matla a khoheli a EP = 5000 Joules, m = 50 kg, g = 10 m/s2.
E botsitsoe :
h?
Jawab :
EP = mgh
5000 = (50)(10)(h)
5000 = lihora tse 500
h = 5000 / 500 = limithara tse 10
Karabo e nepahetseng ke B.
4. Ntho e boima ba 2 kg e hodimo ho lefatshe ka dimithara tse 5. Ho potlaka ka lebaka la matla a khoheli = 10 m/s2. Boiteko bo hlokahalang ho phahamisa ntho ho fihlela bophahamong ba limithara tse 15 ka holim'a lefatše ke…
A. 100 Joule
B. 200 Joule
C. 300 Joule
D. 400 Joule
E. 500 Joule
Puisano:
Hoa tsebahala :
m = 2 kg, h1 = limithara tse 5, h2 = Limithara tse 15, g = 10 m/s2
E botsitsoe :
W?
Jawab :
Mosebetsi (W) = phetoho ea matla a khoheli (EP)2 – EP1).
W = EP2 – EP1
W = mgh2 – mgh1
W = mg (h2 -h1)
W = (2)(10)(15-5) = (2)(10)(10) = 200 Joule.
Karabo e nepahetseng ke B.
