1. Hoʻopili ʻia kahi nuipa 2-kg i kahi pūnāwai. Inā he 4 cm ka lōʻihi o ka pūnāwai, e hoʻoholo i ka ikehu hiki o ka pūnāwai elastic . ʻO ka wikiwiki ma muli o ke kaumaha he 10 m/s 2.
ʻIke ʻia:
Nuipaʻa (m) = 2 kg
Ka wikiwiki ma muli o ke koʻikoʻi (g) = 10 m/s 2
Kaumaha (w) = mg = (2)(10) = 20 N
Hoʻolōʻihi (x) = 4 kenimika = 0.04 m
Makemake ʻia: Ka ikehu hiki o ka pūnāwai elastic
Lōlā:
ʻO ke ʻano o ke kānāwai o Hooke :
F = kx
F = ikaika, k = kūpaʻa puna, x = ka loli o ka lōʻihi o ka puna
Paʻa mau o ka pūnāwai:
k = w / x = 20 / 0.04 = 500 N/m
Ka ikehu hiki o ka pūnāwai elastic:
PE = ½ kx 2 = ½ (500)(0.04) 2 = (250)(0.0016) = 0.4 Joule
Hoʻonā ʻē aʻe:
PE = ½ kx 2 = ½ (w / x) x 2 = ½ wx = ½ mgx
w = kaumaha, m = nuipa, x = ka loli o ka lōʻihi o ka pūnāwai
PE = ½ (2)(10)(0.04) = (10)(0.04) = 0.4 Joule.
ʻAʻole maopopo
2. ʻO ka elongation o ka pūnāwai i hohola ʻia e ka ikaika F = 50 N he 10 cm. He aha ka ikehu hiki o ka pūnāwai elastic inā he 12 cm ka elongation o ka pūnāwai.
ʻIke ʻia:
Hoʻolōʻihi (x) = 10 kenimika = 0.1 m
Ikaika (F) = 50 N
Makemake ʻia : Ka ikehu hiki o ka pūnāwai elastic
Lōlā:
Paʻa mau o ka pūnāwai:
k = F / x = 50 / 0.1 = 500 N/m
ʻO ka ikehu hiki o ka pūnāwai elastic inā he 12 kenimika ka elongation o ka pūnāwai.:
PE = ½ kx 2 = ½ (500)(0.12) 2 = (250)(0.0144) = 3.6 Joule.
ʻAʻole maopopo
3. Kiʻi o F vs x i hōʻike ʻia ma ke kiʻi ma lalo nei. He aha ka ikehu hiki o ka pūnāwai elastic, inā he 10 cm ka elongation o ka pūnāwai.
ʻIke ʻia:
Ikaika (F) = 5 N
ʻO ka hoʻolōʻihi ʻana o ka pūnāwai (x) = 2 kenimika = 0.02 m
Makemake ʻia: ʻO ka ikehu hiki o ka pūnāwai elastic inā he 0.1 m ka elongation o ka pūnāwai.
Lōlā:
Paʻa mau o ka pūnāwai:
k = F / x = 5 / 0.02 = 250 N/m
ʻO ka ikehu hiki o ka pūnāwai elastic inā he 0.1 m ka elongation o ka pūnāwai:
PE = ½ kx 2 = ½ (250)(0.1) 2 = (125)(0.01) = 1.25 Joule.
4. Lele kekahi mea pāʻani ma luna o kahi mea kani puna me ke kaumaha o 500 N, hoʻopōkole ka puna i 4 kenimika. E hoʻoholo i ka nui o ka ikehu hiki ke hoʻoikaika i ka mea pāʻani.
A. 20 Joule
B. 10 Joule
C. 5 Joule
D. 2 Joule
ʻIke ʻia:
Ikaika (F) = 500 N
ʻO ka loli o ka lōʻihi o ka pūnāwai (Δx) = 4 kenimika = 0.04 m
Makemake ʻia: Ka ikehu hiki o ka pūnāwai
Lōlā:
E helu i ke kūpaʻa elastic o kahi pūnāwai me ka hoʻohana ʻana i ka hoohalike o ke kānāwai o Hooke:
k = F / Δx = 500 N / 0.04 m = 12500 N/m
ʻO ka ikehu hiki ke hoʻololi ʻia o ka pūnāwai:
PE = ½ k Δx 2 = ½ (12500)(0.04) 2 = (6250)(0.0016)
PE = 10 Joule
ʻO ka pane pololei ʻo B.
5. He pūnāwai ke kau ʻia me ka nuipa o 500 grams, e piʻi aʻe kona lōʻihi ma 5 cm. E hoʻoholo i kona kūpaʻa a me kona ikehu hiki.
ʻIke ʻia:
Ka nuipa o ka mea (m) = 500 grams = (500/1000) kg = 5/10 kg = 0.5 kg
Hoʻolalelale (g) = 10 m/s 2
Kaumaha o ka mea (w) = mg = (0.5 kg)(10 m/s 2 ) = 5 kg m/s 2 = 5 Newtons
ʻO ka loli o ka lōʻihi o ka pūnāwai (Δx) = 5 kenimika = 0.05 m
Makemake ʻia: ke kūpaʻa o ka pūnāwai (k) a me ka ikehu hiki (PE)
Lōlā:
ʻO ka mea mua, e helu i ke kūpaʻa o ka pūnāwai me ka hoʻohana ʻana i ka hoohalike o ke kānāwai o Hooke:
k = w / Δx = 5 N / 0.05 m = 100 N/m
ʻO ka hiki ke hoʻopili ʻia o ka pūnāwai:
PE = ½ k Δx 2 = ½ (100)(0.05) 2 = (50)(0.0025)
PE = 0.125 Joule
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- Nā pilikia hana i hana ʻia e ka ikaika a me nā hoʻonā
- Nā pilikia a me nā hoʻonā o ka ikehu hana-kinetic
- Nā pilikia a me nā hoʻonā i nā kumumanaʻo ikehu hana-mekanika
- Nā pilikia ikehu hiki ke umekaumaha a me nā hoʻonā
- Ka ikehu hiki ke loaʻa o nā pilikia a me nā hoʻonā o ka pūnāwai elastic
- Nā pilikia mana a me nā hoʻonā
- Ka hoʻohana ʻana i ka mālama ʻana i ka ikehu mechanical no ka neʻe hāʻule manuahi
- Ka hoʻohana ʻana i ka mālama ʻana i ka ikehu mechanical no ka neʻe ʻana i luna a i lalo i ka neʻe hāʻule manuahi
- Ka hoʻohana ʻana i ka mālama ʻana i ka ikehu mechanical no ka neʻe ʻana ma nā ʻili piʻo
- Ka hoʻohana ʻana i ka mālama ʻana i ka ikehu mechanical no ka neʻe ʻana ma ka mokulele inclined
- Ka hoʻohana ʻana i ka mālama ʻana i ka ikehu mechanical no ka neʻe ʻana o ka projectile
