Kumumanaʻo ikehu hana-mekanika
ʻŌlelo ke kumumanaʻo ikehu hana-kinetic ua like ka hana upena a i ʻole ka hana i hana ʻia e ka ikaika upena me ka loli o ka ikehu kinetic.
ʻupena W = TO t – TO o = 1⁄2 m(v t 2 – v o 2 )
W upena = Aia ʻelua ʻano o nā ikaika, ʻo ia hoʻi ka ikaika conservative, a me ka ikaika non-conservative. No laila, hiki ke manaʻo ʻia ka hana upena he hana i hana ʻia e kahi ikaika conservative a me ka hana i hana ʻia e kahi ikaika non-conservative.
W c + W nc = ΔKE
ʻO ka hana i hana ʻia e kahi ikaika conservative ua like ia me ka loli maikaʻi ʻole o ka ikehu hiki:
W c = -ΔPE
– ΔPE + W nc = ΔKE
W nc = ΔPE + ΔKE
Wnc = ΔME
ʻŌlelo ke kaulike ma luna nei ua like ka hana i hana ʻia e kahi ikaika non-conservative ma luna o kahi mea me ka loli o ka ikehu mechanical o ka mea. Ikehu mechanical = ikehu hiki + ikehu kinetic. Hiki i ka ikehu hiki ke lawe i ke ʻano o ka ikehu hiki ke umekaumaha a i ʻole ka ikehu hiki elastic.
Laʻana nīnau: ʻO ke kumumanaʻo ikehu hana-mekanika
Neʻe mua kahi pahu 2 kg i ka wikiwiki o 10 m/s. Ma hope koke iho, kū ka pahu. ʻO ke koina o ka friction kinetic ma waena o ka pahu a me ka papahele he 0.2. ʻO ka wikiwiki o ka umekaumaha he 10 m/s 2. ʻEhia ka neʻe ʻana o ka pahu?
Kōkua:
ʻIke ʻia: m = 2 kg, v o = 10 m/s, vt = 0, k = 0.2, w = mg = (1 kg)(10 m/s 2 ) = 10 kg m/s 2 = 10 Newtons,
Nīnau ʻia: ka nui o ka neʻe ʻana o ka pahu (s)
ʻO ke kumumanaʻo ikehu hana-mekanika:
W nc = ΔME
W nc = ΔPE + ΔKE
ʻO ke kiʻekiʻe (h) e mau ana a i ʻole ʻaʻohe loli o ke kiʻekiʻe, no laila ʻaʻohe loli o ka ikehu hiki ke hoʻoulu ʻia e ka umekaumaha.
Wnc = ΔKE
ʻO ke ʻano o ka hana i hana ʻia e ka ikaika frictional kinetic:
W nc = – f k s = μ k N -s = μ k w -s = μ k mg -s
W nc = – (0.2)(2)(10)(s) = – (4)(s)
Hana ka ikaika frictional kinetic i ka hana maikaʻi ʻole (aia ka ikaika frictional kinetic ma ke kuhikuhi ʻē aʻe mai ka neʻe ʻana o ka mea)
Ka loli ʻana o ka ikehu kinetic:
ΔKE = 1⁄2 m (vt 2 – vo 2 ) = 1⁄2 (2)(0 2 – 10 2 ) = (0 – 100) = – 100
Ka neʻe ʻana o ka mea:
W nc = ΔKE
– (4)(mau) = – 100
s = – 100 / – 4 = 25 mika
20 mau nīnau manaʻo a me nā pane e pili ana i ke kumumanaʻo o ka hana-ikehu mechanical:
1. Nīnau: He aha ke kumumanaʻo o ka ikehu hana-mekanika? Pane: ʻŌlelo ke kumumanaʻo o ka ikehu hana-mekanika ua like ka hana i hana ʻia ma kahi mea me ka loli o kona ikehu mechanical.
2. Nīnau: Pehea ka wehewehe ʻana o ka hana ma ka physics? Pane: Ua wehewehe ʻia ka hana ma ke ʻano he huahana o ka ikaika i hoʻopili ʻia i kahi mea a me ka mamao e neʻe ai i ke kuhikuhi o ka ikaika
3. Nīnau: He aha ka ikehu mechanical? Pane: ʻO ka ikehu mechanical ka ikehu kinetic o kahi mea a me ka ikehu hiki.
4. Nīnau: I ka loaʻa ʻole o nā mana non-conservative, he aha ka mea hiki ke ʻōlelo ʻia e pili ana i ka ikehu mechanical holoʻokoʻa o kahi ʻōnaehana pani? Pane: Noho mau ka ikehu mechanical holoʻokoʻa.
5. Nīnau: E hāʻawi i kahi laʻana o kahi ikaika conservative. Pane: ʻO ka ikaika umekaumaha kahi laʻana o kahi ikaika conservative.
6. Nīnau: Pehea ka ʻokoʻa o ka ikehu hiki ke hana ʻia mai ka ikehu kinetic? Pane: ʻO ka ikehu hiki ke hana ʻia ka ikehu ma muli o ke kūlana, e like me ke kiʻekiʻe ma luna o ka honua, ʻoiai ʻo ka ikehu kinetic ma muli o ka neʻe ʻana.
7. Nīnau: Pehea e pili ai ka hana i hana ʻia e kahi ikaika conservative i ka ikehu hiki? Pane: Ua like ka hana i hana ʻia e kahi ikaika conservative me ka loli maikaʻi ʻole o ka ikehu hiki.
9. Nīnau: Pehea e wehewehe ai ke kumumanaʻo ikehu hana-mekanika i ka hoʻololi ʻana o ka ikehu hiki i ka ikehu kinetic i loko o kahi mea hāʻule manuahi? Pane: I ka hāʻule ʻana o kahi mea, emi iho kona ikehu hiki a piʻi aʻe kona ikehu kinetic ma ka nui like, e mālama ana i ka ikehu mechanical holoʻokoʻa.
10. Nīnau: He aha ka mea e hana ʻia i ka ikehu mechanical o kahi ʻōnaehana ke hana nā ikaika non-conservative, e like me ka friction, ma luna o ia? Pane: Ke emi nei ka ikehu mechanical no ka mea ua hoʻopau nā ikaika non-conservative i ka ikehu, pinepine ma ke ʻano he wela.
11. Nīnau: Hiki i ka ikehu mechanical o kahi ʻōnaehana ke hoʻonui? Pane: ʻAe, ke hana ʻia ka hana waho ma ka ʻōnaehana.
12. Nīnau: Pehea e pili ai ke kumumanaʻo o ka hana i ka ikehu? Pane: ʻO ka hana ke ala e hoʻoili ʻia ai a hoʻololi ʻia ai paha ka ikehu i loko o kahi ʻōnaehana.
13. Nīnau: Inā e neʻe ana kahi mea ma kahi wikiwiki mau, he aha ka mea hiki ke ʻōlelo ʻia e pili ana i ka hana upena i hana ʻia ma luna? Pane: ʻO ka hana upena i hana ʻia ma luna he ʻole no ka mea ʻaʻohe wikiwiki e hana nei.
15. Nīnau: No ke aha i loaʻa ai ka ikehu hiki i kahi pūnāwai i hoʻopaʻa ʻia? Pane: Ke hoʻopaʻa ʻia kahi pūnāwai, hana ʻia ka hana ma luna, kahi i mālama ʻia ma ke ʻano he ikehu hiki. Hiki ke hoʻokuʻu ʻia kēia ikehu ke hoʻokuʻu ʻia ka pūnāwai.
16. Nīnau: He aha ke kumumanaʻo hana-ikehu? Pane: Ke ʻōlelo nei ke kumumanaʻo hana-ikehu ua like ka hana i hana ʻia ma kahi mea me ka loli o kona ikehu kinetic.
17. Nīnau: Pehea ka pili ʻana o ka mana i ka hana? Pane: ʻO ka mana ka wikiwiki o ka hana ʻana a i ʻole ka hoʻoili ʻia ʻana o ka ikehu. Ua helu ʻia ʻo , kahi ʻo ka hana a ʻo ka manawa.
18. Nīnau: Hiki i ka hana ke loaʻa kahi waiwai maikaʻi ʻole? Pane: ʻAe, he maikaʻi ʻole ka hana ke kūʻē ka ikaika a me ke kuhikuhi o ka neʻe ʻana.
19. Nīnau: Inā he 90 degere ke kihi ma waena o ka ikaika a me ke kuhikuhi o ka neʻe ʻana, he aha ka hana i hana ʻia? Pane: ʻO ka hana i hana ʻia he ʻole no ka mea ʻaʻohe ʻāpana o ka ikaika ma ke kuhikuhi o ka neʻe ʻana.
20. Nīnau: Pehea e maʻalahi ai ka hana i kahi mīkini maʻalahi, e like me ka lever? Pane: ʻAʻole hoʻololi ka lever i ka hana holoʻokoʻa i hana ʻia akā hoʻololi i ke ʻano o ka hoʻopili ʻia ʻana o ka ikaika, e hoʻolilo ana i ka hana i ʻoi aku ka maʻalahi a i ʻole ka maikaʻi.
He mea nui ke kumumanaʻo o ka hana a me ke kumumanaʻo ikehu mechanical i ka physics a hāʻawi i kahi ʻike kumu no ke ʻano o ka hoʻoili ʻia ʻana a me ka hoʻololi ʻia ʻana o ka ikehu ma nā ʻōnaehana like ʻole.
