Ka hana i hana ʻia e nā mana conservative Ka ikehu hiki
E nānā i kahi mea e neʻe ana i luna a laila hoʻi i kona kūlana mua ma hope o ka hiki ʻana i ke kiʻekiʻe loa. Ke neʻe nei ka mea i luna aʻe, hana ke kaumaha i ka hana maikaʻi ʻole ma luna o ka mea. Ke neʻe nei ka mea i luna, piʻi ke kiʻekiʻe o ka mea. No laila, piʻi pū ka ikehu hiki ke hoʻopaʻa ʻia o ka mea. Hiki ke hoʻoholo ʻia ua like ka hana maikaʻi ʻole i hana ʻia e ke kaumaha me ka piʻi ʻana o ka ikehu hiki ke hoʻopaʻa ʻia o ka mea (PE).
W = – mgh
W = – mg (h 2 – h 1 ) = – (PE 2 – PE 1 ) = -ΔPE
Ke neʻe pololei nei ka mea i lalo, hana ka ikaika umekaumaha i ka hana maikaʻi ma luna o ka mea. Ke neʻe pololei nei ka mea i lalo, emi iho ke kiʻekiʻe o ka mea. No laila, emi pū ka ikehu hiki ke umekaumaha o ka mea. Hiki ke hoʻoholo ʻia ua like ka hana maikaʻi i hana ʻia e ka ikaika umekaumaha ma luna o ka mea me ka emi ʻana o ka ikehu hiki ke umekaumaha o ka mea.
W = mgh
W = mg (h 1 – h 2 ) = mgh 1 – mgh 2 = – (mgh 2 – mgh 1 ) = – (PE 2 – PE 1 ) = -ΔPE
E nānā i kahi mea i kaomi ʻia i ka hema me ka hopena o kahi pūnāwai (e nānā i ke kiʻi 3). Ke neʻe nei ka mea i ka hema, hana ka ikaika pūnāwai i ka hana maikaʻi ʻole ma luna o ka mea. Ke neʻe nei ka mea i ka hema, piʻi ka ʻokoʻa o ka pūnāwai. No laila, piʻi pū ka ikehu hiki i ka pūnāwai. Hiki ke hoʻoholo ʻia ua like ka hana maikaʻi ʻole i hana ʻia e ka pūnāwai me ka piʻi ʻana o ka ikehu hiki i ka pūnāwai. Ke neʻe nei ka mea i ka ʻākau, hana ka ikaika pūnāwai i ka hana maikaʻi ma luna o ka mea. Ke neʻe nei ka mea i ka ʻākau, emi ka ʻokoʻa o ka pūnāwai. No laila, emi pū ka ikehu hiki i ka pūnāwai. Hiki ke hoʻoholo ʻia ua like ka hana maikaʻi i hana ʻia e ka pūnāwai ma luna o ka mea me ka emi ʻana o ka ikehu hiki i ka pūnāwai.
Wahi a ka wehewehe ʻana ma luna, hiki ke ʻōlelo ʻia ua like ka hana i hana ʻia e kahi ikaika conservative me ka loli o ka ikehu hiki o ka mea. Ke hana ka ikaika conservative i ka hana maikaʻi, e emi ana ka ikehu hiki. I ka ʻaoʻao ʻē aʻe, ke hana ka ikaika conservative i ka hana maikaʻi ʻole, e piʻi ana ka ikehu hiki. No laila, ua like ka hana i hana ʻia e kahi ikaika conservative me ka loli maikaʻi ʻole o ka ikehu hiki.
W c = -ΔPE
Laʻana nīnau 6: Hana ma o ka ikaika conservative a me ka ikehu hiki
Aia kahi mea me ke kaumaha o 1 kg ma ke kiʻekiʻe o 5 mika ma luna o ka ʻilikai honua. ʻO ka wikiwiki o ka umekaumaha he 10 m/s 2. E hoʻoholo (a) ka hana i hana ʻia e ke kaumaha ke hoʻoneʻe ʻia ka mea i kahi kiʻekiʻe o 10 mika ma luna o ka ʻilikai honua, (b) ka hana e pono ai e hoʻoneʻe i ka mea i kahi kiʻekiʻe o 10 mika, a me (c) ka loli o ka ikehu hiki ke umekaumaha o ka mea ke hoʻoneʻe ʻia ka mea i kahi kiʻekiʻe o 10 mika.
Kōkua:
Ua ʻike ʻia: m = 1 kg, g = 10 m/s 2 ,
(a) Hana ma ke kaupaona
W = – mg Δh
= – (1 kg)(10 m/s 2 )(5 m) = – 50 Joules
Hana ke kaumaha i ka hana maikaʻi ʻole no ka mea ʻokoʻa ke kuhikuhi o ke kaumaha i ke kuhikuhi o ka neʻe ʻana o ka mea.
(aia ke kaumaha i lalo, aia ka neʻe ʻana o ka mea i luna).
(b) Hana ma o ka ikaika hāpai
I mea e hiki ai ke hāpai ʻia ka mea, pono e like ka ikaika hāpai liʻiliʻi loa me ke kaumaha.
= (1 kg)(10 m/s 2 )(5 m) = 50 Joules
W = wh = mg Δh
He maikaʻi ka hana i hana ʻia e ka ikaika hāpai no ka mea like ke kuhikuhi o ka ikaika me ka neʻe ʻana.
(aia ka ikaika hāpai i luna, aia ka neʻe ʻana i luna)
(c) Ka loli ʻana o ka ikehu hiki
ΔPE = mg Δh
ΔPE = 50 Joule
Piʻi ka ikehu hiki ke hoʻopaʻa ʻia o ka mea ma 50 Joules.
20 mau nīnau manaʻo a me nā pane e pili ana i ka hana i hana ʻia e nā mana conservative a me ka ikehu hiki:
1. Nīnau: He aha nā mana conservative? Pane: ʻO nā mana conservative nā mana nona ka hana i hana ʻia he kūʻokoʻa ia mai ke ala i lawe ʻia.
2. Nīnau: Pehea e pili ai ka hana i hana ʻia e kahi ikaika conservative i ka loli o ka ikehu hiki? Pane: Ua like ka hana i hana ʻia e kahi ikaika conservative me ka loli maikaʻi ʻole o ka ikehu hiki.
3. Nīnau: E inoa i kahi laʻana maʻamau o kahi ikaika conservative. Pane: ʻO ka ikaika umekaumaha kahi laʻana maʻamau o kahi ikaika conservative.
4. Nīnau: No ke aha i manaʻo ʻole ʻia ai ka friction he ikaika conservative? Pane: No ka mea, ʻo ka hana i hana ʻia e ka friction e pili ana i ke ala i lawe ʻia.
5. Nīnau: Pehea e hōʻike ʻia ai ka ikehu hiki ke umekaumaha o kahi mea kokoke i ka ʻili o ka Honua? Pane: Hōʻike ʻia ka ikehu hiki ke umekaumaha ma ke ʻano he ℎ , kahi ʻo m ka nuipa, ʻo g ka wikiwiki ma muli o ke umekaumaha, a ʻo h ke kiʻekiʻe ma luna o kahi kiko kuhikuhi.
6. Nīnau: Hiki i ka ikehu hiki ke lilo i mea maikaʻi ʻole? Pane: ʻAe, hiki i ka ikehu hiki ke lilo i mea maikaʻi ʻole ma muli o ke koho ʻana o ke kiko kuhikuhi.
8. Nīnau: Inā piʻi ka ikehu hiki o kahi ʻōnaehana, he aha ka mea e hana ʻia i ka ikehu kinetic, me ka manaʻo ʻaʻohe hana waho i hana ʻia? Pane: E emi ana ka ikehu kinetic ma ka nui like me ka piʻi ʻana o ka ikehu hiki, e mālama ana i ka mālama ʻana i ka ikehu mechanical.
9. Nīnau: He aha nā kūlana no ka mālama ʻana i ka ikehu mechanical? Pane: Mālama ʻia ka ikehu mechanical ke hana wale nā mana conservative ma kahi ʻōnaehana.
10. Nīnau: I loko o kahi ʻōnaehana pani kahi e hana wale ai nā mana conservative, he aha ka mea hiki ke ʻōlelo ʻia e pili ana i ka ikehu mechanical holoʻokoʻa? Pane: Noho mau ka ikehu mechanical holoʻokoʻa.
11. Nīnau: Pehea e hoʻoholo ʻia ai ka ikehu hiki o kahi uku uila i loko o kahi kahua uila? Pane: ʻO ka ikehu hiki , kahi ʻo q ka uku a ʻo V ka hiki.
12. Nīnau: No ke aha e hoʻonui ai ka hāpai ʻana i kahi mea i loko o ke kahua umekaumaha i kona ikehu hiki? Pane: No ka mea, hana ʻia ka hana e kūʻē i ka ikaika umekaumaha e hāpai i ka mea, kahi e mālama ʻia ma ke ʻano he ikehu hiki.
13. Nīnau: Pehea e hana ʻia ai ka hana e kahi ikaika conservative i loko o kahi loop pani? Pane: ʻO ka hana upena i hana ʻia e kahi ikaika conservative ma luna o kahi loop pani he zero.
14. Nīnau: Pehea e pili ai ka ikehu hiki i ke kūpaʻa? Pane: Ma nā wahi i emi loa ai ka ikehu hiki, ua paʻa ka ʻōnaehana.
15. Nīnau: Hiki i nā mea ʻelua ma nā kiʻekiʻe like ʻole ke loaʻa ka ikehu hiki ke hoʻohana ʻia e like me ka umekaumaha? Pane: ʻAe, hiki iā lākou, ma muli o ke koho ʻana o ka pae kuhikuhi no ka ikehu hiki.
16. Nīnau: No ke aha mākou e koho pinepine ai i ka honua ma ke ʻano he kiko kuhikuhi no ka ikehu hiki ke hoʻohana ʻia e ka umekaumaha? Pane: Hāʻawi ia i kahi kuhikuhi kūpono a maopopo loa, ʻoiai hiki ke koho ʻia kekahi kiko.
17. Nīnau: I loko o kahi ʻōnaehana kaʻawale me nā ikaika conservative wale nō, inā emi ka ikehu hiki i ka 10 J, pehea ka nui o ka loli o ka ikehu kinetic? Pane: Piʻi ka ikehu kinetic i ka 10 J.
18. Nīnau: Pehea e pili ai ka ikehu hiki i ka ikaika ma nā kahua conservative? Pane: ʻO ka ikaika ka gradient maikaʻi ʻole o ka ikehu hiki.
19. Nīnau: Inā hoʻoneʻe ʻia kahi mea ma ke kuhikuhi o kahi ikaika conservative, pehea e loli ai kona ikehu hiki? Pane: E emi ana kona ikehu hiki.
20. Nīnau: Hiki i kahi mea ke loaʻa ka ikehu kinetic akā ʻaʻohe ikehu hiki? Pane: ʻAe, pili ia i ke koho ʻana o ke kiko kuhikuhi no ka ikehu hiki.
Uhi kēia mau nīnau a me nā pane i nā manaʻo koʻikoʻi e pili ana i nā mana conservative a me ka ikehu hiki, ka mea e hana nei i kahi ʻāpana koʻikoʻi o ka mechanics classical.
