Botenya ke mohopolo oa bohlokoa fisiks o rutoang boemong ba sekolo se phahameng sa bana ba banyenyane, haholo-holo sehlopheng sa bo7. Khopolo ena e thusa baithuti ho utloisisa hore na boima ba ntho bo amana joang le bophahamo ba eona. Sehloohong sena, re tla buisana ka tlhaloso ea botenya, mokhoa o sebelisitsoeng, le mehlala e meng ea mathata ho hlakisa kutloisiso ea baithuti.
Tlhaloso ea Botenya
Botenya ke tekanyo ea mahloriso a boima ba ntho ka bongata bo fanoeng. Ka mantsoe a mang, botenya bo bontša hore na thepa e teteaneng hakae. Botenya bo ka hlalosoa ka mokhoa o latelang:
\[ \rho = \frac{m}{V} \]
Di mana:
– \(\rho\) (bala: rho) ke bongata.
– \(m\) ke boima ba ntho.
– \(V\) ke bophahamo ba ntho.
Yuniti ea SI ea bongata ke lik'hilograma ka mithara ea likhubu (kg/m³). Leha ho le joalo, ligrama ka sentimetara ea likhubu (g/cm³) le tsona li atisa ho sebelisoa maemong a manyenyane.
Bohlokoa ba Botenya
Botenya ke thepa ea bohlokoa haholo hobane:
1. Tlhahlobo ea Thepa: Thepa ka 'ngoe e na le bongata bo ikhethang. Ka ho tseba bongata, re ka khetholla thepa.
2. Moralo le Boenjiniere: Moralong oa sehlahisoa, ho hlokahala hore ho nahanoa ka bongata ba thepa ho fumana matla le botsitso ba sebopeho.
3. Ditshebediso tsa Diindasteri: Botenya bo sebediswa ditshebedisong tse fapaneng tsa diindasteri tse kang tlhahiso ya disebediswa, mabenyane, jj.
Foromo ea Botenya
Ho bala bongata, re sebelisa foromo e boletsoeng ka holimo:
\[ \rho = \frac{m}{V} \]
Mohlala oa Tšebeliso ea Foromo
A re re re na le ntho e boima ba digrama tse 200 le bophahamo ba 50 cm³. Ebe, boima ba yona bo ka balwa ka tsela e latelang:
\[ \rho = \frac{200 \, \text{g}}{50 \, \text{cm}^3} = 4 \, \text{g/cm}^3 \]
Lipotso tsa Mehlala le Puisano ea Bongata
Mohlala oa Potso ea 1
Potso:
Lefika le na le boima ba digrama tse 300 le bophahamo ba 100 cm³. Bala boima ba lefika.
Puisano:
Hoa tsebahala:
– Boima (\(m\)) = digrama tse 300
– Bophahamo (\(V\)) = 100 cm³
Ho sebelisa foromo ea bongata:
\[ \rho = \frac{m}{V} = \frac{300 \, \text{g}}{100 \, \text{cm}^3} = 3 \, \text{g/cm}^3 \]
Kahoo, boima ba lefika ke 3 g/cm³.
Mohlala oa Potso ea 2
Potso:
Boloko ba lehong bo na le bophahamo ba 2.000 cm³ le boima ba 0,6 g/cm³. Boima ba boloko ba lehong ke bokae?
Puisano:
Hoa tsebahala:
– Bophahamo (\(V\)) = 2.000 cm³
– Botenya (\(\rho\)) = 0,6 g/cm³
Ho sebelisa foromo ea density e hlophisitsoeng bocha ho fumana boima:
\[ m = \rho \times V = 0,6 \, \text{g/cm}^3 \times 2.000 \, \text{cm}^3 = 1.200 \, \text{g} \]
Kahoo, boima ba boloko ba lepolanka ke digrama tse 1.200 kapa 1,2 kg.
Mohlala oa Potso ea 3
Potso:
Ntho e boima ba digrama tse 500 e na le boima ba 2,5 g/cm³. Bophahamo ba ntho eo ke bokae?
Puisano:
Hoa tsebahala:
– Boima (\(m\)) = digrama tse 500
– Botenya (\(\rho\)) = 2,5 g/cm³
Ho sebelisa foromo ea density e hlophisitsoeng bocha ho fumana bophahamo ba modumo:
\[ V = \frac{m}{\rho} = \frac{500 \, \text{g}}{2,5 \, \text{g/cm}^3} = 200 \, \text{cm}^3 \]
Kahoo, bophahamo ba ntho eo ke 200 cm³.
Mohlala oa Potso ea 4
Potso:
Haeba tšepe e nang le bophahamo ba 250 cm³ e na le boima ba 2 kg, bala bongata ba tšepe ka diyuniti tsa kg/m³.
Puisano:
Hoa tsebahala:
– Bophahamo (\(V\)) = 250 cm³ = 0,00025 m³ (hobane 1 m³ = 1.000.000 cm³)
– Boima (\(m\)) = 2 kg
Ho sebelisa foromo ea bongata:
\[ \rho = \frac{m}{V} = \frac{2 \, \text{kg}}{0,00025 \, \text{m}^3} = 8.000 \, \text{kg/m}^3 \]
Kahoo, boima ba tšepe ke 8.000 kg/m³.
Mohlala oa Potso ea 5
Potso:
Seithuti se lekanya boima ba mokelikeli 'me se fumana hore ke ligrama tse 250. Haeba bophahamo ba mokelikeli e le 200 cm³, boima ba mokelikeli ka g/cm³ ke bofe?
Puisano:
Hoa tsebahala:
– Boima (\(m\)) = digrama tse 250
– Bophahamo (\(V\)) = 200 cm³
Ho sebelisa foromo ea bongata:
\[ \rho = \frac{m}{V} = \frac{250 \, \text{g}}{200 \, \text{cm}^3} = 1,25 \, \text{g/cm}^3 \]
Kahoo, boima ba mokelikeli ke 1,25 g/cm³.
Mohlala oa Potso ea 6
Potso:
Ntho e chitja e na le boima ba 7,8 g/cm³ le bophahamo ba 500 cm³. Boima ba ntho eo ke bokae?
Puisano:
Hoa tsebahala:
– Botenya (\(\rho\)) = 7,8 g/cm³
– Bophahamo (\(V\)) = 500 cm³
Ho sebelisa foromo ea density e hlophisitsoeng bocha ho fumana boima:
\[ m = \rho \times V = 7,8 \, \text{g/cm}^3 \times 500 \, \text{cm}^3 = 3.900 \, \text{g} \]
Kahoo, boima ba ntho eo ke digrama tse 3.900 kapa 3,9 kg.
Qetello
Botenya ke mohopolo wa motheo fisiks o hlalosang kamano pakeng tsa boima le bophahamo ba ntho. Foromo ya bongata, \( \rho = \frac{m}{V} \), e sebediswa ho bala bongata, boima, kapa bophahamo ba ntho ha ho tsejwa tse pedi ho tse tharo. Ho utlwisisa mohopolo ona ho bohlokwa bakeng sa baithuti ba sehlopha sa bosupa hobane ho fana ka motheo wa ho ithuta mehopolo e rarahaneng ya fisiks nakong e tlang.
Mehlala ea mathata a fanoeng sehloohong sena e lebelletsoe ho thusa baithuti ho utloisisa mokhoa oa ho sebelisa mokhoa oa ho sebelisa foromo ea ho ba le bongata maemong a fapaneng. Ka boikoetliso bo lekaneng, baithuti ba tla be ba itokiselitse hamolemo litlhahlobo le mesebetsi e amanang le mohopolo oa ho ba le bongata.
