He tuhinga mō te ture nekehanga a Newton
1. Te whakamāramatanga o te kaha
Ko te kaha he mea e whakateretere ai ngā mea. Arā, ko te kaha he mea e neke ana, e aukati ana, e whakarerekē ana rānei i te ahunga o te nekehanga o tētahi mea. He rahinga whārite te kaha, nō reira, he rahi me te ahunga tōna. Ko te tohu kaha ko F (Kaha). Ko te F he tohu whānui mō te kaha. He maha ngā momo kaha, ā, kāore i te katoa ngā kaha e whai tohu F. Ko te waeine pūnaha ā-ao ko kg m/s2 e mōhiotia ana ko Newton.
2. Te whakamāramatanga o te kaha kupenga
Ko te kaha hua (ΣF) ko te tapeke o ngā kaha katoa e pā ana ki tētahi mea. He rahinga whārite te kaha, nō reira ka tatauhia te kaha katoa i runga i te ture tāpiri whārite.
Ko te kaha katoa = 10 Newton, ko te ahunga o te kaha katoa ki te taha matau.
Ko te kaha katoa = 8 Newton, ko te ahunga o te kaha katoa ki te taha matau.
Te kaha katoa = 0
Te kaha katoa = 0
3. Ngā ture nekehanga a Newton
Ko ngā ture nekehanga a Newton ko ngā ture ahupūngao e pā ana ki te nekehanga o tētahi mea i whakatakotoria e te tohunga ahupūngao Ingarihi, a Isaac Newton.
3.1 Te Ture Tuatahi a Newton
E mea ana te Ture Tuatahi a Newton me noho tonu ngā mea katoa e okioki ana, me ngā mea katoa rānei e neke tika ana i te tere pumau
ka haere tonu te neke tika i te tere pūmau mēnā he kore te kaha katoa e pā ana ki te mea.
ΣF = 0
He tauākī pāngarau tēnei whārite mai i te ture tuatahi a Newton.
Tirohia tētahi mea e karapoti ana i a koe, pērā i te tēpu, i te kōhatu, i tētahi atu mea rānei. Ka noho okioki tonu te tēpu e takoto ana mēnā kāore i nekehia, kāore rānei i tukuna he kaha o waho pērā i te pana, te tō rānei. Kāore he kaha e mahi ana ki ngā tēpu, ki ngā toka, ki ngā mea rānei e takoto ana? He kaha kei te mahi ki te mea, engari ko te tapeke o ngā kaha katoa e mahi ana ki te mea, ki te kaha katoa rānei, he kore. Ko ngā kaha e mahi ana ki ngā mea kei runga tonu i te mata o ngā aorangi pērā i te whenua ko te kaha ā-papa (w) me te kaha noa (N). Ko te ahunga o te kaha ā-papa he poutū ki waenganui o te whenua, ko te ahunga o te kaha noa he poutū ki runga. He rite te rahi o ēnei kaha e rua, engari he rerekē te ahunga, nō reira he ōrite te kaha katoa ki te kore.
Ā, me pēhea ngā mea e neke tika ana me te tere pumau? Hei whakamārama i tēnei raruraru, me kī ka panaia e koe tētahi mea, hei tauira, he wahi whakarewa, ki runga i te mata o te papa. Whai muri i te panaia, ka puhoi te whakarewa, ka mutu nā te waku. Kia neke haere atu, kia roa ake rānei ngā wahi whakarewa, me whakangawari te mata o te papa me te mata o te pereti whakarewa. Mena he maeneene te mata o te papa, ā, kāore he waku, ka haere tonu te nekehanga o te pereti whakarewa, ā, kāore e mutu. Kāore he kaha e pā ana ki te pereti whakarewa e neke ana i runga i te mata o te papa tino maeneene? He kaha kei runga i ngā pereti whakarewa, arā, ko te kaha o te taumaha me te kaha noa. Ka mahi poutū ēnei kaha e rua, ā, kāore e pā ki te nekehanga o ngā pereti whakarewa i te taha whakapae mena he maeneene te papa.
E ai ki te Ture Tuarua a Newton, ki te kore te kaha katoa e pā ana ki tētahi mea e ōrite ana ki te kore, ka tere ake te mea. He rite te rahi o te tere ki te rahi o te kaha katoa, ā, he rite whakamuri ki te papatipu o te mea. He rite te ahunga o te tere ki te ahunga o te kaha katoa.
ΣF = ma
ΣF = te kaha katoa (kg m/s 2 ), m = te papatipu (kg), a = te whakaterenga (m/s 2 )
Ko te whārite 1.2 he tauākī pāngarau mai i te ture tuarua a Newton.
Mena he ōrite te whakaterenga ki te kore (a = 0) ka huri te whārite 1.2 ki te whārite 1.1. Nō reira, ko te ture tuatahi a Newton he take motuhake o te ture tuarua a Newton. I runga i te whārite 1.2 ka whakatauhia ko te nui ake o te kaha, ko te nui ake o te whakaterenga. i tetahi atu taha, ko te nui ake o te papatipu, ko te iti ake o te whakaterenga. Ka mārama ake te whanaungatanga i waenga i te kaha, te papatipu, me te whakaterenga i muri i tō whakahaere i tētahi whakamātautau e pā ana ki tēnei.
Tauira raruraru 1:
Whakatauhia te rahi me te ahunga o te whakaterenga o ngā mea i runga i te ahua i runga ake nei…
Rongoā:
ΣF = ma
4 kg m/s 2 = (1 kg) a
a = 4 kg m/s 2 : 1 kg = 4 m/s 2
Ko te rahi o te whakaterenga = 4 m/s² , te ahunga o te whakaterenga ki te taha matau.
Tauira raruraru 2:
Whakatauhia te rahi me te ahunga o te whakaterenga i runga i te ahua i runga ake nei …
Rongoā:
ΣF = ma
4 kg m/s 2 – 1 kg m/s 2 = (1 kg) a
3 kg m/s 2 = (1 kg) a
a = 3 kg m/s 2 : 1 kg
a = 3 m/s 2
Ko te rahi o te whakaterenga = 3 m/s² , te ahunga o te whakaterenga ki te taha matau.
3.2.1 Taumaha (w)
Ko te taumaha te kaha o te papatipu e pā ana ki tētahi mea papatipu.
ΣF = ma
w = mg
Ko te whārite 1.3 te whārite mō te tatau i te taumaha o tētahi mea.
w = taumaha (kg m/s 2 ), m = papatipu (kg), g = whakaterenga o te kaha ā-papatipu (m/s 2 ). Ko te rahi o te whakaterenga kaha ā-papatipu (g) i runga i te mata o te whenua ko 9.8 m/s 2 . Hei whakahaere i ngā tātaitanga, ka whakaawhiwhia a g ki te 10 m/s 2.
3.2.2 Te kaha noa (N)
Ko te kaha noa ko te kaha e pā ana ki ngā mea e rua e pā ana tetahi ki tetahi, ā, ko te ahunga o te kaha noa e poutū ana ki te mata o te papa pā.
Mātakihia ngā mea kei runga tonu i te mata o te tēpu. Ka pā anō hoki te kaha o te papa taumaha ki te mea. Kāore ngā mea e taka noa ana pērā i te hua e taka ana mai i te rākau nā te mea he kaha noa. He rite tonu te taumaha (w) me te kaha noa (N) engari he rerekē ngā ahunga, nō reira ko te kaha katoa ki runga i te mea he kore.
ΣF = 0
N – w = 0
N = w
3.3 Te Ture Tuatoru a Newton
E ai ki te ture tuatoru a Newton, mēnā ka tukuna e te mea 1 te kaha ki te mea 2, ka tukuna anō hoki e te mea 2 te kaha ki te mea 1. He rite tonu ngā kaha e rua, engari he rerekē te ahunga o ngā kaha e rua. Ka kiia tētahi kaha he mahi, ka kiia tētahi he tauhohenga.
Mahi F = – Tauhohenga F
Ko te whārite 1.3 he kōrero pāngarau mai i te ture tuatoru a Newton. Ko te tohu kino i te whārite 1.3 e whakamārama ana i te ahunga o te kaha.
Whakamātauria kia mārama ake ai koe ki te ture tuatoru o Newton. Mena he papa reti tāu, panaia te pakitara i a koe e tū ana i runga i te papa reti. I muri i te pana i te pakitara, ka neke whakamuri te papa reti. Ko te ahunga o tō kaha kei mua, ko te ahunga o te papa reti kei muri.
E tohu ana tēnei ka whakamanahia koe e te pakitara. Ina panaia e koe te pakitara, i te wā kotahi, ka panaia koe e te pakitara. Ka mahi tō kaha pana ki te pakitara, ko te kaha pana o te pakitara ia ka mahi ki a koe. He rite tonu ngā kaha e rua engari he rerekē ngā ahunga. Ka taea e koe te kī ko tētahi kaha he mahi, ko tētahi atu he tauhohenga.
Ko tētahi atu whakamātautau ka taea te mahi ko te pupuhi i tētahi poihau rapa, ā, i muri i te whakawhanuitanga o te poihau rapa nā te mea kua kī i te hau, ka tukuna te poihau. I muri i te tukunga, kei te "rere" te poihau. Ko te ahunga o te nekehanga o te poihau he ritenga kē ki te ahunga o te putanga o te hau mai i te poihau. Me pēhea te whakamārama i tēnei?
Ina tukuna te waha o te poihau, ka panaia te hau ki waho e te poihau. I taua wā anō, ka panaia hoki te poihau e te hau. Mā te kaha pana hau ka rere te poihau. Ka mahi te kaha o te poihau, ka mahi te kaha o te hau ki runga i te poihau. He rite tonu ngā kaha e rua, engari he rerekē te ahunga.
Mātakihia te ahua 2, ka whakataurite ki te ahua 3. Ko te kaha noa e pā ana ki tētahi mea (N) ko te kaha e tukuna ana e tētahi mata papatahi, pērā i te mata tēpu. I taua wā anō, ka tukuna hoki e ngā mea te kaha ki te mata tēpu (N'). He rite te rahi o ēnei kaha noa e rua (N me N'), engari kei ngā ahunga rerekē, ā, he rerekē te mahi i runga i ngā mea. Kāore i rite ki a w me N he rite te rahi, ā, he rite te mahi i runga i te mea kotahi. Nō reira, he kaha mahi-tauhohenga a N me N'.
