Nā nīnau hoʻohālike ʻoihana

9 mau laʻana o nā nīnau ʻoihana

1. Hoʻopili ʻia kahi ikaika o 20 Newtons i kahi poloka a hiki i ka neʻe ʻana o ka poloka i kahi mamao o 2 mika. ʻO ka hana i hana ʻia e ka ikaika F ma ka poloka…
Pahana
Ua ʻike ʻia :
Ikaika (F) = 20 N
Ka neʻe ʻana (s) = 2 mika
Huina = 0 (ua like ke kuhikuhi o ka ikaika me ke kuhikuhi o ka neʻe ʻana a i ʻole kūlike ke kuhikuhi o ka ikaika me ke kuhikuhi o ka neʻe ʻana i ʻole ke kihi i hoʻokumu ʻia e ka ikaika a me ka neʻe ʻana he ʻole)
Ua nīnau ʻia : Hoʻoikaika (W)
Pane :
Catatan:
Inā like ke kuhikuhi o ka ikaika me ke kuhikuhi o ka neʻe ʻana, e helu i ka hana me ka hoʻohana ʻana i ke ʻano hana W = F s, me ka ʻole o ka pono e hoʻohui i ka cos ʻanakē.

2. Kū paʻa kahi mea ma luna o kahi papahele laumania. Hoʻopili ʻia kahi ikaika F = 10 N i ka mea, e hana ana i kahi kihi o 30^o e kūʻē i ka papahele. Inā neʻe ka mea i 1 mika, ehia ka hana i hana ʻia e ka ikaika F ma luna o ka mea?
Pahana
Ua ʻike ʻia :
Ikaika (F) = 10 Newtons
ʻO ka ikaika ma ke kuhikuhi o ka neʻe ʻana (F_x) = F cos 30^o = (10)(0,5√3) = 5√3 Newtons
Ka neʻe ʻana (s) = 1 mika
Ua nīnau ʻia : hoʻoikaika (W) ?
Pane :
W = F_x s = (5√3)(1) = 5√3 Joule

3. Hāʻule kūʻokoʻa kahi mea me ke kaumaha o 1 kg mai ke kiʻekiʻe o 2 mika. Inā he 10 m/s ka wikiwiki ma muli o ke kaumaha², e hoʻoholo i ka hana i hana ʻia e ka ikaika umekaumaha ma luna o ka mea!
Pahana
Ua ʻike ʻia :
Ka nuipa o ka mea (m) = 1 kg
Kiʻekiʻe (h) = 2 mika
Ka wikiwiki ma muli o ke koʻikoʻi (g) = 10 m/s²
Ua nīnau ʻia Hana i hana ʻia e ka ikaika umekaumaha ma luna o kahi mea (W)
Pane :
ʻO ke kuhikuhi o ka ikaika umekaumaha a i ʻole ke kaumaha (w) he kū pololei i lalo, ʻo ke kuhikuhi o ka neʻe ʻana o ka mea (s) he kū pololei hoʻi i lalo i like ai ka ikaika umekaumaha me ka neʻe ʻana o ka mea.
W = Fs = wh = mgh
W = (1)(10)(2) = 20 Joule

4. Ua kau ʻia kahi pūnāwai me kahi ukana o ke kaumaha he 1 kg i ʻike ai ka pūnāwai i ka piʻi ʻana o ka lōʻihi o 2 cm. Inā he 10 m/s ka wikiwiki ma muli o ke kaumaha², e hoʻoholo (a) ke kūpaʻa puna (b) ka hana i hana ʻia e ka puna ma luna o ka ukana
Pahana
Ua ʻike ʻia :
Nuipaʻa (m) = 1 kg
Ka wikiwiki ma muli o ke koʻikoʻi (g) = 10 m/s²
Ka hoʻonui ʻana i ka lōʻihi o ka pūnāwai (x) = 2 kenimika = 0,02 mika
Ua nīnau ʻia : ke kūpaʻa o ka pūnāwai a me ka hana i hana ʻia e ka ikaika pūnāwai
Pane :
(a) Paʻa mau o ka pūnāwai
ʻO ke ʻano hana o ke kānāwai o Hooke :
F = k-x.
E hoʻohuli i kēia ʻano hana e helu ai i ke kūpaʻa puna:
k = F / x = w / x = mg / x
k = (1)(10) / 0,02 = 10 / 0,02
k = 500 Newton/mika
(b) Hana i hana ʻia e ka ikaika puna
W = – ½ kx²
W = – ½ (500)(0,02)²
W = – (250)(0,0004)
W = -0,1 Joule
He maikaʻi ʻole ka hana i hana ʻia e ka ikaika puna ma luna o ka ukana no ka mea ua kūʻē ke kuhikuhi o ka ikaika puna i ke kuhikuhi o ka neʻe ʻana o ka ukana.

5. Ua hoʻolalelale ʻia kahi pahu e waiho ana ma luna o ka papahele me ka ikaika o 10 N i neʻe ai ka pahu i kahi mamao o 2 mika. Inā like ka mana paʻi me ka neʻe ʻana o ka pahu a ua hana ʻia ka pahu e ka ikaika kinetic friction o 2 Newtons, a laila ʻo ka hana holoʻokoʻa i hana ʻia ma ka pahu he...
Pahana
Ua ʻike ʻia :
Ikaika (F) = 10 Newtons
Ka ikaika kuʻi kinetic (F_k) = 2 Newton
Ka neʻe ʻana (s) = 2 mika
Ua nīnau ʻia : Ka hoʻoikaika holoʻokoʻa (W_Nui)
Pane :
Hana i hana ʻia me ka ikaika (F):
W₁ = Fs cos 0 = (10)(2)(1) = 20 Joules
ʻO ka hana i hana ʻia e ka ikaika friction kinetic (F_k):
W₂ =F_k s = (2)(2)(cos 180) = (2)(2)(-1) = -4 Joules
ʻO ka hoʻoikaika holoʻokoʻa:
W_Nui = W₁ - W₂
W_Nui = 20 - 4
W_Nui = 16 Joule

6. Aia kahi mea me ke kaumaha o 5 kg he 10 mika ma luna o ka ʻili o ka Honua. ʻO ka wikiwiki ma muli o ke koʻikoʻi = 10 m/s^-2ʻO ka nui o ka ikaika e pono ai e hoʻoneʻe i ka mea i ke kiʻekiʻe o 15 mika mai ka ʻili o ka honua he...

A. . 75 Joule

B. . 250 Joule

C. . 500 Joule

D. . 750 Joule

E. 1.250 Joule

Pahana

Ua ʻike ʻia:

Ka nuipa o ka mea (m) = 5 kg

Kiʻekiʻe (h) = 10 mika

Ka wikiwiki ma muli o ke koʻikoʻi (g) = 10 m/s²

Ua nīnau ʻia: E hoʻāʻo e hoʻoneʻe i kahi mea i ke kiʻekiʻe o 15 mika

Pane:

ʻO ka hoʻoikaika e hoʻoneʻe i kahi mea ma ka liʻiliʻi he like ia me ka ikaika umekaumaha e hana ana ma luna o ka mea.

ʻO ke ʻano hana no ka hana i hana ʻia e ka ikaika o ke kaumaha:

W = wh = mgh

Wehewehe: W = ka hoʻoikaika ʻana, w = umekaumaha, h = kiʻekiʻe, m = nuipa, g = wikiwiki o ka umekaumaha

ʻO ke ʻano hana no ka hana i hana ʻia:

W = wh = mgh = (5 kg)(10 m/s)²)(10 mika) = 500 kg mika²/s² = 500 Joule

ʻO C ka pane pololei.

7. Ke neʻe nei kahi mea me ke kaumaha o 2 kg ma luna o kahi ʻili laumania ma ka wikiwiki o 2 m/s.^-1 . Ma hope o kekahi mau manawa, neʻe ka mea i ka wikiwiki o 5 ms^-1 ʻO ka hana i hana ʻia ma ka mea i loko o kēia wā...

A. 4 Joule

B. 9 Joule

C. 15 Joule

D. 21 Joule

E. 25 Joule

Pahana

Ua ʻike ʻia:

Ka nuipa o ka mea (m) = 2 kg

Ka wikiwiki mua (v_o) = 2 ms^-1

Ka wikiwiki hope loa (v_t) = 5 ms^-1

Ua nīnau ʻia: Ka hana i hana ʻia ma luna o kahi mea i loko o kēlā manawa

Pane:

ʻŌlelo ke kumumanaʻo ikehu hana-kinetic e like ka hana holoʻokoʻa i hana ʻia ma kahi mea me ka loli o ka ikehu kinetic o ka mea. Ma ke ʻano makemakika:

W = ΔEK = EK₂ – EK₁ = 1/2 mv_t² – 1/2 mv_o² = 1/2 m (v_t² - v_o²) = 1/2 (2)(5²-2²) = (1)(25-4) = 21 Joule

8. Ua hoʻomaha mua kahi papaʻaina me ke kaumaha o 10 kg ma luna o kahi papahele laumania, i paʻi ʻia no 3 kekona, e neʻe ana ma kahi laina pololei me ka wikiwiki o 2 m/s.^-2ʻO ka nui o ka hoʻoikaika i hana ʻia…

A. 20 Joule

B. 30 Joule

C. 60 Joule

D. 180 Joule

E. 360 Joule

Pahana

Ua ʻike ʻia :

Nuipaʻa (m) = 10 kg

Ka wikiwiki mua (v_o) = 0 (i ka wā mua, ua paʻa ka papaʻaina)

Ka manawa (t) = 3 kekona

Hoʻolalelale (a) = 2 m/s²

Ua nīnau ʻia : hoʻoikaika (W) ?

Pane :

ʻO ka mea mua, e helu i ka mamao i hele ʻia me ka hoʻohana ʻana i ke ʻano GLBB:

s = v_o t + ½ ma² = (0)(3) + ½ (2)(3)²

s = 0 + (1)(9) = 9

Nā hana i hana ʻia ma ka papaʻaina:

W = Fs = (ma)(s) = (10)(2)(9) = 180 Joules

ʻO D ka pane pololei.

9. SUa paʻi ʻia i luna kahi poloka me ke kaumaha o 1,5 kg e ka ikaika mau F = 15 N ma luna o kahi mokulele hilig e like me ka mea i hōʻike ʻia ma ke kiʻi. Manaʻo ʻia ʻo ka wikiwiki ma muli o ke koʻikoʻi (g) he 10 m/s.^-2 a ʻo ka friction ma waena o ka poloka a me ka mokulele inclined he zero. ʻO ka hana holoʻokoʻa i hana ʻia ma ka poloka he…

A. 15 J

B. 30 J

C. 35 J

D. 45 J

E. 50 J

Pahana

Ua ʻike ʻia :

Ka nuipa o ka poloka (m) = 1,5 kg

Ka wikiwiki ma muli o ke koʻikoʻi (g) = 10 m/s²

Kaumaha o ka poloka (w) = mg = (1,5)(10) = 15 Newton

Ka ikaika hoʻokuʻi (F) = 15 Newton

Ua nīnau ʻia : ka huina o ka hana i hana ʻia ma ka poloka (W) ?

Pane :

ʻElua mau mana e hana ana ma ka poloka; ka mana e like me ka neʻe ʻana o ka poloka, ʻo ia hoʻi ka mana hoʻokuke (F) a me ke kaumaha o ka poloka e like me ka ʻili o ka mokulele inclined (w)._x).

ʻO ka hana i hana ʻia e ka ikaika e hoʻoneʻe ana:

W₁ = Fs = (15 N)(2 m) = 30 N m = 30 Joules

Hana i hana ʻia e ka umekaumaha wx:

W₂ = w_x s = (w sin 30^o)(2 m) = (15 N)(1/2)(2 m) = 15 N m = 15 Joules

Ka huina o ka hana i hana ʻia ma ka poloka:

W_Nui = W₁ - W₂ = 30 J – 15 J = 15 Joule

ʻO A ka pane pololei.