Te momo kāhua tiaki me te momo kāhua kore-tiaki

1. Kāhua Matatika
Mena he ōrite ki te kore te mahi i mahia e tētahi kaha i te tīmatanga o te neke o tētahi mea mai i tōna tūranga tīmatanga tae noa ki te hokinga o te mea ki tōna tūranga tīmatanga, ka kiia te kaha he kaha pūmau.
Anei ētahi tauira o ngā momo kāhua pūmau.

1.1. Te kaha ā-papatipu
Whakaarohia tētahi mea e neke poutū ana ki runga kia tae rā anō ki tōna teitei mōrahi, kātahi ka neke ki raro ki tōna tūranga taketake. I a ia e neke poutū ana ki runga i te tawhiti h, kei te taha kē te kaha o te papatipu i te nekehanga o te mea. Nā te mea kei te taha kē i te nekehanga o te mea, ka mahi kino te kaha o te papatipu ki te mea.
W = wh cos (180^o) = – wh = – mgh
I muri i te ekenga ki tōna teitei rawa, ka neke te mea ki raro ki tōna tūranga taketake mā te tawhiti h. Ina neke ki raro, ka rite te ahunga o te kaha o te papatipu ki te nekehanga o te mea. Nā te mea kei te rite te ahunga ki te nekehanga, ka mahi pai te kaha o te papatipu.
W = wh cos (0^o) = – wh = – mgh
He rite tonu te papatipu o te mea (m), te whakaterenga ā-papatipu (g) ​​me te teitei (h), nō reira ko te mahi i mahia e te kaha ā-papatipu ina tīmata te mea ki te neke poutū ki runga tae noa ki tōna hokinga ki tōna tūranga taketake he ōrite ki te kore.
W = mgh – mgh
W = 0

1.2. Te kaha o te puna
Whakaarohia he puna e whakatakotoria whakapae ana. Mēnā ka panaia, ka pēhia rānei te pito matau o te puna ki te taha maui, ka tukuna hoki e te puna he kaha ki te taha matau. Ka taea e koe te whakaatu i tēnei mā te pēhi i te puna. Hei tauira, whakatakotoria he mea ki te pito matau o te puna, kātahi ka pēhi ki te taha maui. I muri i te peka o te puna, tangohia tō ringa i te taumaha me te puna. Ina kore tō ringa e pā ki te puna, kei te panaia te taumaha e te mea ki te taha matau. Ina neke te mea ki te taha maui, ko te ahunga o te nekehanga o te mea he ritenga kē atu i te ahunga o te kaha o te puna. Nā te mea kei ngā ahunga kē te kaha, ka mahi kino te kaha o te puna.
W = – ½ kx²
Ina neke te mea ki te taha matau, ka rite te ahunga o te nekehanga, te nekehanga rānei o te kawenga ki te ahunga o te kaha o te puna. Nā te mea kei te ahunga kotahi rāua, ka mahi pai te kaha o te puna.
W = ½ kx²
He rite tonu ngā puna e whakamahia ana, nō reira he rite tonu te pūmau puna (k). He rite anō hoki te nekehanga o te puna. Nō reira, ko te mahi i mahia e te kaha ā-papa ina tīmata te neke o te mea ki te taha maui i te tawhiti x, kātahi ka hoki ki te taha matau i te tawhiti x, he ōrite ki te kore.
W = ½ kx² – ½ kx²
Ko te mahi i mahia e te kaha ā-papa me te kaha puna i te wā e neke ana te mea mai i tōna tūranga tīmatanga tae noa ki tōna hokinga ki tōna tūranga taketake he kore. Mena he kore te mahi i mahia e te kaha i te wā e tīmata ana te neke o te mea mai i tōna tūranga tīmatanga tae noa ki tōna hokinga ki tōna tūranga taketake, ka kiia te kaha he kaha pūmau.

2.      Kāhua kore-pūmau

Ki te kore te mahi i mahia e tētahi kaha i te tīmatanga o te neke o tētahi mea mai i tōna tūranga tīmatanga tae noa ki tōna hokinga ki tōna tūranga taketake e ōrite ki te kore, ka kiia taua kaha he kaha kore-pūmau.
Anei ētahi tauira o ngā momo tohu pūmau.
2.1 Te kaha pana me te kaha waku nekeneke
Whakaarohia tētahi mea e panaia ana ki te taha matau, kātahi ka panaia anō ki te taha maui. Ina neke, ina neke rānei ki te taha matau, ko te ahunga o te nekehanga o te mea he rite ki te ahunga o te kaha pana (F) ā, he rerekē ki te ahunga o te kaha waku nekeneke (f)._kNā te mea kei te ahunga kotahi ki te nekehanga, ka mahi pai te kaha pana ki te mea.
W = Fs

I tētahi atu taha, ka mahi kino te waku nekeneke ki tētahi mea.
W = – f_k s
Ina neke, ina neke rānei te mea ki te taha mauī, ka rite te ahunga o te nekehanga o te mea ki te ahunga o te kaha pana, ā, ka rerekē ki te ahunga o te kaha waku nekeneke. Nā te mea kei te ahunga kotahi ki te nekehanga, ka mahi pai te kaha pana ki te mea.
W = Fs
I tētahi atu taha, ka mahi kino te waku nekeneke ki tētahi mea.
W = – f_k s
Ko te mahi i mahia e te kaha pana me te kaha waku nekeneke i runga i tētahi mea ina tīmata te neke o te mea mai i tōna tūranga tīmatanga tae noa ki tōna hokinga ki tōna tūranga tīmatanga ko W = 2 F s me W = -2 f_k s
Kāore te mahi i mahia e te kaha pana me te kaha waku nekeneke i te wā e neke ana te mea mai i tōna tūranga tīmatanga tae noa ki te hokinga atu ki tōna tūranga tīmatanga e ōrite ana ki te kore.
Ki te kore te mahi i mahia e tētahi kaha i te tīmatanga o te neke o tētahi mea mai i tōna tūranga tīmatanga tae noa ki tōna hokinga ki tōna tūranga taketake e ōrite ki te kore, ka kiia taua kaha he kaha kore-pūmau.

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