Kumumanaʻo ikehu hana-mekanika

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.

W_upena = I_t – IĀ_o = 1⁄2 m(v_t² - v_o²)

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 ʻupena 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/s²ʻEhia ka neʻe ʻana o ka pahu?

Kōkua:

Ua ʻike ʻia: m = 2 kg, v_o = 10 m/s, vt = 0, k = 0.2, w = mg = (1 kg)(10 m/s²) = 10 kg m/s² = 10 Newton,

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 = μk mg -s

W_nc = – (0.2)(2)(10)(mau) = – (4)(mau)

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 (v_t² - v_o²) = 1/2 (2)(0² - 10²) = (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 mai: ʻŌlelo ke kumumanaʻo o ka ikehu hana-mechanical ua like ka hana i hana ʻia ma kahi mea me ka loli o kona ikehu mechanical.

2. Nīnau: Pehea e wehewehe ʻia ai ka hana ma ka physics? pane mai: 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 ia ma ke kuhikuhi o ka ikaika

3. Nīnau: He aha ke ʻano o ka ikehu mechanical? pane mai: 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 mai: ʻO ka ikehu mechanical holoʻokoʻa e mau ana.

5. Nīnau: E hāʻawi i kahi laʻana o kahi mana conservative. pane mai: ʻO ka ikaika umekaumaha kahi laʻana o ka ikaika conservative.

6. Nīnau: Pehea ka ʻokoʻa o ka ikehu hiki ke loaʻa mai ka ikehu kinetic? pane mai: 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 mai: 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-mechanical i ka hoʻololi ʻana o ka ikehu hiki i ka ikehu kinetic i loko o kahi mea hāʻule manuahi? pane mai: 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 mana non-conservative, e like me ka friction, ma luna o ia? pane mai: Ke emi nei ka ikehu mechanical no ka mea ua hoʻopau nā mana non-conservative i ka ikehu, pinepine e like me ka wela.

11. Nīnau: Hiki ke hoʻonui ʻia ka ikehu mechanical o kahi ʻōnaehana? pane mai: ʻAe, ke hana ʻia ka hana waho ma ka ʻōnaehana.

12. Nīnau: Pehea e pili ai ka manaʻo o ka hana me ka ikehu? pane mai: ʻO ka hana ke ala e hoʻoili ʻia ai ka ikehu a hoʻololi ʻia paha i loko o kahi ʻōnaehana.

13. Nīnau: Inā e neʻe ana kahi mea ma ka wikiwiki mau, he aha ka mea e hiki ke ʻōlelo ʻia e pili ana i ka hana upena i hana ʻia ma luna ona? pane mai: ʻO ka hana upena i hana ʻia ma luna he ʻole no ka mea ʻaʻohe hoʻolalelale e hana ʻia ana.

15. Nīnau: No ke aha i loaʻa ai ka ikehu hiki i kahi pūnāwai i hoʻopaʻa ʻia? pane mai: Ke kaomi ʻia kahi pūnāwai, hana ʻia ka hana ma luna ona, 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 mai: ʻŌlelo ke kumumanaʻo hana-ikehu ua like ka hana i hana ʻia ma kahi mea me ka loli o kona ikehu kinetic.

17. Nīnau: Pehea e pili ai ka mana i ka hana? pane mai: ʻO ka mana ka wikiwiki o ka hana ʻana a i ʻole ka hoʻoili ʻia ʻana o ka ikehu. Ua helu ʻia e like me $P=W/t$, kahi $W$ he hana a $t$ ʻo ia ka manawa.

18. Nīnau: Hiki i ka hana ke loaʻa kahi waiwai maikaʻi ʻole? pane mai: ʻAe, 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 mai: 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 uea? pane mai: 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 ʻoi aku ka maʻalahi o ka hoʻokele a i ʻole ka maikaʻi o ka hana.

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.