Te mātāpono o te Pūngao Mahi-Kinetika
Ki te mahi te kaha kupenga ki runga i tētahi mea, ka pāngia te mea e te whakaterenga (ka pāngia te mea e te nekehanga). Ina pāngia te mea e te whakaterenga, ka rerekē te tere o te mea. Arā, ko te mahi i mahia e te kaha kupenga e pā ana ki te tere tīmatanga me te tere whakamutunga o te mea.
Ko te mahi i mahia ki runga i tētahi mea mā te kaha kupenga pumau ko:
W kupenga = ΣF s
E ai ki te ture tuarua a Newton, mēnā he kaha kupenga e mahi ana ki runga i tētahi mea, ka pāngia taua mea e te whakaterenga.
W kupenga = (ma) s
Mena he pumau te kaha kupenga, he pumau anō hoki te whakaterenga e pā ana ki te mea. Nō reira, ka taea e tātou te whakakapi i te whakaterenga (a) me te nekehanga (s) ki tētahi whārite nekehanga rārangi kore-taurite.
Whakauruhia te whārite nekehanga rārangi kore-taurite ki te whārite mahi:
Whakaahuatanga: EK t = te pūngao nekeneke whakamutunga, EK o = te pūngao nekeneke tīmatanga, m = te papatipu, v t = te tere whakamutunga, v o = te tere tīmatanga
Ko tēnei whārite te ariā pūngao mahi-nekeneke. Mā te ariā pūngao mahi-nekeneke e whakamōhio mai ki a tātou ko te mahi kupenga, arā, ko te mahi i mahia e te kaha kupenga ki runga i tētahi mea, he ōrite ki te huringa o te pūngao nekeneke o te mea. E whakamōhio mai ana hoki ki a tātou ko te pūngao nekeneke o tētahi mea he ōrite ki te mahi kupenga e hiahiatia ana hei whakatere i te mea mai i te āhua tūmau ki te neke i tētahi tere kua whakaritea, me te ritenga kē.
Tauira pātai 5: Te ariā pūngao mahi-nekeneke
Ka neke tetahi motuka he 1000 kg te taumaha mai i te āhua tūmau. I roto i tētahi wā poto, ka piki te tere ki te 10 m/s. E hia te nui o te mahi kupenga e mahia ana e ngā miihini o te motuka?
Rongoā:
E mōhiotia ana: m = 1000 kg, v o = tere tīmatanga = 0 m/s (i te tīmatanga, kei te okioki te motuka), v t = tere whakamutunga = 10 m/s
E hiahiatia ana: Te whatunga
W kupenga = 1⁄2 m (v t 2 – v o 2 )
W kupenga = 1⁄2 (1000)(10 2 – 0 2 ) = (500)(100 – 0) = (500)(100) = 50,000 Joule
1. He aha te mātāpono o te Pūngao Mahi-Kinetika? E kī ana te mātāpono o te Pūngao Mahi-Kinetika ko te mahi kupenga i mahia ki runga i tētahi mea he ōrite ki te huringa o tōna pūngao nekeneke. I roto i te pāngarau, , ko te pūngao nekeneke whakamutunga tangohia te pūngao nekeneke tīmatanga.
2. He aha te hononga o te mahi ki te huringa o te tere o tētahi mea? Ka taea e te mahi i mahia ki tētahi mea te whakarerekē i tōna tere. Ina koa, ko te mahi kupenga i mahia ki tētahi mea he ōrite ki te huringa o tōna pūngao nekeneke, ā, ko te pūngao nekeneke e pā ana ki te tapawhā o te tere. Nō reira, ki te mahia he mahi kupenga pai ki tētahi mea, ka piki ake tōna tere (nō reira ko tōna pūngao nekeneke).
3. Ka pēhea te kaha nekeneke o tētahi mea ina mahia he mahi kino ki runga? Ina mahia he mahi kino ki runga i tētahi mea, ka heke tōna kaha nekeneke. Tērā pea ka pōturi te haere o te mea.
4. He aha te hononga o te mātāpono o te Pūngao Mahi-Kinetic ki te ture tuarua a Newton? E whakaahua ana te ture tuarua a Newton i te pānga o te kaha ki te nekehanga o tētahi mea, ko te mātāpono ia o te Pūngao Mahi-Kinetic e hono ana i te mahi i mahia e taua kaha ki te huringa o te pūngao kinetic. E honoa ana ngā ariā e rua mā te whakaaro ka taea e ngā kaha te whakarerekē i te āhua o te nekehanga me te pūngao o tētahi mea.
5. Ka taea te kī he kino te pūngao nekeneke o tētahi mea? Kāo, ehara i te mea kino tonu te pūngao nekeneke. Ka hoatuhia tēnei e te tātai , ko m te papatipu, ā, ko v te tere. Nā te mea he pai te papatipu me te tapawhā o te tere, he pai anō hoki te pūngao nekeneke, he kore rānei.
6. Me pēhea te pānga o te mātāpono Mahi-Pūngao Kinetic ki tētahi mea e neke ana i te ara porowhita? Mō tētahi mea e neke ana i te ara porowhita i te tere pumau, ka noho pumau tonu tōna pūngao kinetic nā te mea kāore tōna tere e rerekē. Heoi, ka huri tonu te ahunga o tōna tere. Mena ko ngā kaha porotītaha anake (pēnei i te taumahatanga, te kaha ā-papa rānei) ka pā ki te mea, ko te mahi i mahia e ēnei kaha he kore i te mea ka mahi poutū ki te ahunga nekehanga. Nō reira, kāore he mahi kupenga e mahia ana, ā, kāore he huringa o te pūngao kinetic.
7. I te korenga o ngā kaha o waho, me pēhea te hurihanga o te pūngao nekeneke o tētahi mea? I te korenga o ngā kaha o waho, kāore he mahi e mahia ana ki te mea, ko te tikanga ka noho pūmau tonu tōna pūngao nekeneke. He whakaaturanga tēnei o te tiakitanga o te pūngao.
8. He aha te tikanga ina kore te mahi kupenga i mahia ki tētahi mea? Ina kore te mahi kupenga i mahia ki tētahi mea, ko te tikanga kāore te pūngao nekeneke o te mea i rerekē. Tērā pea kei te neke tonu te mea, engari kei te pumau tonu tōna tere.
9. Ka taea e te mea te whai pūngao nekeneke ahakoa kāore he mahi i mahia ki runga? Ae, ka taea e te mea te whai pūngao nekeneke me te kore he mahi e mahia ki runga i roto i tētahi wā kua whakaritea. Hei tauira, ka mau tonu te pūngao nekeneke o te mea kua neke kē i te wāhi o waho (kei tawhiti atu i ngā tinana ā-papa) me te neke tonu i te tere pumau, ahakoa kāore he kaha o waho e pā ki runga.
10. He aha te pānga o te mahi a ngā kaha kore-pūmau ki te pūngao nekeneke o tētahi mea? Ka taea e te mahi a ngā kaha kore-pūmau te whakanui ake, te whakaiti rānei i te pūngao nekeneke o tētahi mea, i runga i te ahunga me te rahi o te kaha e pā ana ki te nekehanga o te mea. Hei tauira, ko te waku, he kaha kore-pūmau, he mahi kino te nuinga, ā, ka whakaitihia te pūngao nekeneke o tētahi mea.
