Ikehu mīkini - nā pilikia a me nā hoʻonā

Ikehu mīkini - nā pilikia a me nā hoʻonā

ʻO ke kumumanaʻo hana-ikaika mechanical

1. ʻO ke koina o ka friction kinetic ma waena o ka poloka a me ka papahele (μ _k ) he 0.5. He aha ka neʻe ʻana o kahi mea (mau mea)? ʻO ka wikiwiki ma muli o ke koʻikoʻi he 10 m/s ².

ʻIke ʻia:

ʻO ke koina o ka friction kinetic (μ _k ) = 0.5

Ka nuipa o ka poloka (m) = 4 kg

ʻO ka wikiwiki ma muli o ke koʻikoʻi (g) he 10 m/s ²

Kaumaha o ka poloka (w) = mg = (4)(10) = 40 Newtons

Inā ʻo ka poloka ma ka mokulele ʻākea a laila ʻo ka ikaika maʻamau (N) = kaumaha (w) = 40 Newtons.

Inā ʻo ka poloka ma ka mokulele ʻākea a laila ʻo ka ikaika maʻamau (N) = kaumaha (w) = 40 Newtons.

Ka wikiwiki mua (v ₁ ) = 5 m/s

Ka wikiwiki hope loa (v ₂ ) = 0 m/s

Makemake ʻia: ka neʻe ʻana o ka mea (d)?

Lōlā:

ʻŌlelo ke kumumanaʻo ikehu hana-mekanika ua like ka hana (W) i hana ʻia e ka ikaika nonconservative me ka loli o ka ikehu mechanical o kahi mea. ʻO ka loli o ka ikehu mechanical = ka ikehu mechanical hope loa - ka ikehu mechanical mua.

ʻO ka ikaika friction kinetic kekahi o nā ikaika nonconservative a ʻo ia wale nō ka ikaika nonconservative e hana ana ma ka poloka.

W = ΔME

f _k d = ME ₂ – ME ₁

Nā hana i hana ʻia e ka ikaika friction kinetic:

W = f _k d = (μ _k )(N)(d) = (0.5)(40)(d) = 20 d

Ka loli o ka ikehu mechanical:

ΔME = ME ₂ – ME ₁ = (KE + PE) ₂ – (KE + PE) ₁

Neʻe ka mea ma ka mokulele ʻākea a ʻaʻohe loli o ke kiʻekiʻe (Δh = 0) no laila ʻaʻohe loli o ka ikehu hiki ke hoʻopaʻa ʻia (ΔPE = PE ₂ - PE ₁ = 0). No laila, ʻo ka loli o ka ikehu mechanical e pili wale ana i ka loli o ka ikehu kinetic.

ΔME = KE ₂ – KE ₁ = ½ mv ₂ ² – ½ mv ₁ ² = ½ m (v ₂ ² – v ₁ ² )

Δ M E = ½ (4)(0 ² – 5 ² ) = (2)(25) = 50

Ka hoʻoneʻe ʻana o ka poloka:

W = ΔME

20 kekona = 50

s = 50 / 20

s = 2.5 mika

Ke kumumanaʻo o ka mālama ʻana i ka ikehu mechanical

2. Ua like ke kaumaha o ka mea A a me ka mea B. Hāʻule manuahi ʻo ka mea A mai ke kiʻekiʻe o h mika a hāʻule manuahi ʻo ka mea B mai ke kiʻekiʻe o 2h mika. Inā paʻi ka mea A i ka honua ma vm/s, a laila he aha ka ikehu kinetic o ka mea B i kona paʻi ʻana i ka honua.

Lōlā:

ʻO ka wikiwiki hope loa o ka mea B i ka wā e hāʻule kūʻokoʻa ana mai ke kiʻekiʻe o 2h:

v ² = 2 g (2h) = 4 gh

ʻO ka ikehu kinetic o ka mea B:

Iā _B = ½ mv ² = ½ m (4 gh) = 2 mgh —– kaulike 1

ʻO ka ikehu mechanical mua o ka mea B = ka ikehu hiki ke umekaumaha = mg h.

ʻO ka ikehu mechanical hope loa o ka mea B = ka ikehu kinetic = ½ ^mv².

ʻO ke kumumanaʻo o ka mālama ʻana i ka ikehu mechanical:

mgh = ½ mv ²

No ka mea ʻo mgh = ½ mv ² a laila hiki iā kākou ke hoʻololi i ka mgh ma ka hoohalike 1 me ½ mv ².

ʻO ka ikehu kinetic o ka mea B = 2 mgh = 2(½ mv ² ) = mv ²

3. Hāʻule manuahi kahi mea mai ke kiʻekiʻe o 20 mika. ʻO ka wikiwiki ma muli o ke koʻikoʻi he 10 m/s. He aha ka wikiwiki o ka mea he 15 mika ma luna o ka honua?

Lōlā:

ʻO ka ikehu mechanical hope loa = ka ikehu mechanical mua

ʻO ka ikehu kinetic ma ke kiko 2 = ka loli o ka ikehu hiki ke umekaumaha a hiki i 5 mika.

4. Ua hoʻokuʻu ʻia kahi poloka mai luna mai o ka mokulele ʻālohilohi. He aha ka wikiwiki o ka poloka i kona wā e pā ai i ka honua?

Lōlā:

ʻO ka ikehu mechanical mua = ka ikehu hiki ke hoʻopaʻa ʻia = mgh = m (10)(5) = 50 mika

ʻO ka ikehu mechanical hope loa = ka ikehu kinetic = 1/2 mv ²

ʻO ke kumumanaʻo o ka mālama ʻana i ka ikehu mechanical, ʻōlelo ʻia ʻo ka ikehu mechanical mua = ka ikehu mechanical hope loa.

ʻO wau _o = ʻO wau _t

50 m = 1/2 mv ²

50 = 1/2 v ²

2 (50) = v ²

100 = v ²

v = 10 m/s

5.

He poloka me ke kaumaha o m-kg i hoʻokuʻu ʻia mai ke kiʻekiʻe o h mika ma luna o ka honua, e like me ka mea i hōʻike ʻia ma ke kiʻi ma lalo nei. E hoʻoholo i ka lakio o ka ikehu hiki i ka ikehu kinetic (KE) ma kahi M.

Lōlā:

ʻO ka ikehu hiki ke hoʻopaʻa ʻia ma ke kiko M:

PE _M = mg (0.3 h)

ʻO ka ikehu kinetic ma ke kiko m = ka loli o ka ikehu hiki ke hoʻopaʻa ʻia e like me h-0.3h = 0.7 h

KE _M = PE = mg (0.7 h)

ʻO ka lakio o ka ikehu hiki ke hoʻopaʻa ʻia e ka umekaumaha i ka ikehu kinetic ma kahi M:

PE _M : KE _M

mg (0.3 hola) : mg (0.7 hola)

0.3: 0.7

3: 7

6. Inā loaʻa iā PE _Q a me KE _Q ka ikehu hiki a me ka ikehu kinetic ma ke kiko Q (g = 10 m/s ² ), a laila PE _Q : KE _Q =…

Lōlā:

ʻO ka ikehu hiki ke hoʻopaʻa ʻia ma kahi Q:

PE _Q = mgh = (m)(10)(1.8) = 18 mika

ʻO ka ikehu kinetic ma ke kiko Q = ka loli o ka ikehu hiki ke hoʻoulu ʻia e ka umekaumaha a hiki i ka 5-1.8 = 3.2 mika

I _Q = PE = mgh = m (10)(3.2) = 32 m

ʻO ka lakio o ka ikehu hiki ke hoʻouluulu ʻia i ka ikehu kinetic ma kahi Q:

PE _Q : KE _Q

18 mika: 32 mika

18: 32

9: 16

1. He aha ka ikehu mechanical? paneʻO ka ikehu mechanical ka huina o ka ikehu hiki a me ka ikehu kinetic i loko o kahi ʻōnaehana. Hōʻike ia i ka nui o ka ikehu e pili ana i ka neʻe ʻana a me ke kūlana o kahi mea.
2. Pehea ka ʻokoʻa o ka ikehu kinetic mai ka ikehu hiki? paneʻO ka ikehu kinetic ka ikehu o ka neʻe ʻana, ʻoiai ʻo ka ikehu hiki ke hana ʻia ka ikehu i mālama ʻia ma muli o ke kūlana a i ʻole ke ʻano o kahi mea. No ka laʻana, he ikehu kinetic ko ke kaʻa e neʻe ana, ʻoiai he ikehu hiki ko ka pūnāwai i kīkoʻo ʻia a i ʻole kahi mea ma ke kiʻekiʻe i loko o ke kahua umekaumaha.
3. Ua mālama mau ʻia ka ikehu mechanical? paneMa kahi ʻōnaehana pani kūpono me ka ʻole o nā ikaika o waho, mālama ʻia ka ikehu mechanical. Eia nō naʻe, i nā kūlana maoli, hiki ke komo mai nā ʻano ikehu ʻē aʻe e like me ka ikehu thermal a i ʻole ke kani ma muli o ka friction a i ʻole nā ​​​​ikaika ʻē aʻe ʻaʻole conservative, e alakaʻi ana i ka emi ʻana o ka ikehu mechanical holoʻokoʻa.
4. Pehea e kōkua ai ka mālama ʻana i ka ikehu mechanical i ka hoʻoponopono ʻana i nā pilikia? paneKe mālama ʻia ka ikehu mechanical i loko o kahi ʻōnaehana (ʻaʻohe ikaika non-conservative e like me ka friction), ua like ka ikehu holoʻokoʻa ma ka hoʻomaka me ka ikehu holoʻokoʻa ma ka hopena. ʻAe kēia kumumanaʻo iā mākou e hoʻopili i nā ikehu hiki a me nā ikehu kinetic ma nā wahi like ʻole o ka manawa, e hoʻomaʻalahi ana i ke kaʻina hana hoʻoponopono pilikia.
5. He aha ka mea e hana ʻia i ka ikehu mechanical o kahi pōpō ke kiola ʻia i luna a kū iki ma mua o ka iho ʻana i lalo? paneI ka piʻi ʻana o ka pōpō, e emi ana kona ikehu kinetic aʻo ka piʻi ʻana o kona ikehu hiki. I ka piko, ʻo kona ikehu mechanical āpau he ikehu hiki. I kona iho ʻana, e hoʻohuli ʻia kēia kaʻina hana. I kahi kūlana kūpono me ka ʻole o ke kū'ē ʻana o ka ea, e mau ana ka ikehu mechanical holoʻokoʻa o ka pōpō i kona huakaʻi.
6. Hiki i kahi mea ke loaʻa ka ikehu kinetic a me ka ikehu potential i ka manawa like? paneʻAe, hiki i kahi mea ke loaʻa nā ʻano ikehu ʻelua i ka manawa like. No ka laʻana, he ikehu kinetic ka pendulum ma waenakonu o kona luliluli ʻana ma muli o kona neʻe ʻana a me ka ikehu hiki ke loaʻa ma muli o kona kiʻekiʻe ma luna o kona wahi haʻahaʻa loa.
7. Pehea e hōʻike ai ka roller coaster i ka mālama ʻana i ka ikehu mechanical? paneHoʻomaka kahi kaʻa holo lio me ka ikehu hiki ke loaʻa ma kona wahi kiʻekiʻe loa. I kona iho ʻana, hoʻololi kēia ikehu hiki ke loaʻa i ka ikehu kinetic, e hoʻonui ana i ka wikiwiki o ka kaʻa holo. I kona piʻi hou ʻana, emi ka ikehu kinetic ʻoiai e piʻi ana ka ikehu hiki ke loaʻa. Ke nānā ʻole nei i ka friction a me ke kū'ē ʻana o ka ea, kokoke mau ka ikehu mechanical holoʻokoʻa.
8. He aha nā mea e hiki ai ke alakaʻi i ka nalowale o ka ikehu mechanical i nā ʻōnaehana honua maoli? paneʻO ka haʻalulu, ke kū'ē ʻana o ka ea, a me ka hana ʻana o ke kani kekahi mau mea e hiki ai ke alakaʻi i ka nalowale o ka ikehu i nā ʻōnaehana honua maoli. ʻAʻole i luku ʻia ka ikehu (ma muli o ke kānāwai o ka mālama ʻana i ka ikehu) akā ua hoʻololi ʻia i nā ʻano ʻē aʻe e like me ka wela a i ʻole ke kani.
9. He aha ka pilina ma waena o ka hana a me ka ikehu mechanical? paneʻO ka hana i hana ʻia ma kahi ʻōnaehana e nā mana o waho e hiki ke alakaʻi i kahi loli i ka ikehu mechanical o ka ʻōnaehana. Ma nā huaʻōlelo makemakika, ua like ka hana me ka loli o ka ikehu mechanical.

10. Inā pili ka ikehu hiki ke hoʻopaʻa ʻia i kahi kiko kuhikuhi, pehea lā e hiki ai iā kākou ke ana mau i nā loli i loko? Pane : ʻOiai ʻo ka waiwai paʻa o ka ikehu hiki ke hoʻopaʻa ʻia e hilinaʻi maoli ʻia i ke koho ʻana o ke kiko kuhikuhi, kūlike nā loli i ka ikehu hiki (e like me ka wā e hāpai ʻia ai a hoʻohaʻahaʻa ʻia paha kahi mea) me ka nānā ʻole i ka kuhikuhi. No laila, hoʻoikaika pinepine mākou i nā loli i ka ikehu hiki ma mua o nā waiwai paʻa.