Te kaha pupuhi - ngā raruraru me ngā otinga
1. He poraka rakau, ko te roa = 2.5 m, ko te whānui = 0.5 m, ā, ko te teitei = 0.4 m. Ko te mātotoru o te wai he 1000 kg/m3 . Mena ka whakanohoia te poraka ki roto i te wai, he aha te kaha pōrewarewa … Ko te whakaterenga nā te kaha ā-papa he 10 N/kg.
Mōhiotia:
Te rōrahi o te poraka (V) = te roa x te whānui x te teitei = 2.5 x 0.5 x 0.4 = 0.5 m3
Te mātotoru o te wai (ρ) = 1000 kg/ m3
Te whakaterenga nā te kaha ā-papa (g) = 10 N/kg
E hiahiatia ana: Te rahi o te kaha pōrewarewa
Rongoā:
Te tātai o te kaha pōrewarewa:
F = ρ g V
F = te kaha pōrewarewa , ρ = te mātotoru o te wai , g = te whakaterenga nā te kaha ā-papa , V = te rōrahi
F = (1000)(10)(0.5) = (1000)(5) = 5000 Ngā Niutona
2. Ko te taumaha o tētahi mea i te hau he 100 N. Ka whakanohoia te mea ki roto i tētahi wai. Ko te pikinga o te rōrahi o te wai he 1.5 m³ . Mena ko te taumaha motuhake o te wai he 10 N/m³ , he aha te taumaha o te mea i roto i te wai.
Mōhiotia:
Taumaha o te mea i te hau (w) = 100 Newton
Te pikinga o te rōrahi o te wai = te rōrahi o te mea i roto i te wai (V) = 1.5 m3
Taumaha motuhake o te wai = 10 N/m 3
E hiahiatia ana: Te taumaha o te mea i roto i te wai
Rongoā:
Taumaha o te mea i roto i te wai = te taumaha o te mea i roto i te hau – te kaha pōrewarewa
Taumaha o te mea i roto i te wai = 100 Newton – te kaha pōrewarewa
Te tātai o te kaha pōrewarewa:
F A = ρ g V
F A = te kaha pōrewarewa = te kaha e pā ana ki te mea i roto i te wai e ngā wai
ρ = te mātotoru o te wai
g = te whakaterenga nā te kaha ā-papa
V = te rōrahi o te mea i roto i te wai
Taumaha motuhake:
Taumaha motuhake o te wai = 10 N/m 3
w / V = 10 N/m 3
mg / V = 10 N/ m3
m (10) / V = 10 N/m 3
m / V = 1 kg/ m3
ρ = 1 kg/ m3
Ko te mātotoru o te wai he 1 kg/ m³
Te rahi o te kaha pōturi :
F A = ρ g V = (1 kg/m³ ) (10 m/s² ) (1.5 m³ ) = 15 kg m/s² = 15 Newton
Te taumaha o te mea i roto i te wai:
Taumaha o te mea i roto i te wai = 100 Newton – 15 Newton
Taumaha o te mea i roto i te wai = 85 Newtons
3. He kaipuke e rere ana i te moana e tomo ana ki tētahi awa whānui, hohonu hoki. Ko te mātotoru o te wai moana he 1100 kg/m³ , ko te mātotoru o te wai awa he 1000 kg/ m³ . Whakatauhia te whakatairite i te rōrahi o te mea kei roto i te wai moana me te mea kei roto i te wai awa.
A. 11 : 10
B. 10 : 11
C. 121 : 100
D. 1 : 1
Mōhiotia:
Te mātotoru o te wai moana (ρ 1 ) = 1100 kg/m 3
Te mātotoru o te wai awa (ρ 2 ) = 1000 kg/m 3
E hiahiatia ana: Te whakataurite i te rōrahi o te mea kei roto i te wai moana me te wai awa. Te whakataurite i te rōrahi o te mea kei roto i te wai moana me te wai awa.
Rongoā:
Mena kei te mānu te mea , ko te kaha pōrewarewa (F B ) = te taumaha (w):
E ai ki te mātāpono a Ākirīmite , ko te kaha pōturi e pā ana ki tētahi mea i roto i te wai (wai) he ōrite ki te taumaha o te wai (wai) e nekehia ana e ia. Ko te rōrahi o te mea i roto i te wai (wai) he ōrite ki te rōrahi o te wai (wai) e nekehia ana.
Te whakataurite i te rōrahi o te mea i roto i te wai moana me te rōrahi o roto wai awa:
Ko te whakautu tika ko B.
4. Ko te koura, ko tōna taumaha he 193 karamu, kei roto i te hinu karāhe, ā, ko tōna kaha whakarunga he 8000 dynes. Mena ko te whakaterenga nā te kaha ā-papa he 10 m/s² , ā, ko te mātotoru o te hinu karāhe he 0.8 gr/cm² , tātaihia te mātotoru o te koura.
A. 1.93 karamu/cm 3
B. 8.65 karamu/cm 3
C. 19.3 karamu/cm 3
D. 193 karamu/cm 3
Mōhiotia:
Taumaha koura (m koura ) = 193 karamu = 0.193 kg
Te whakaterenga nā te kaha ā-papa (g) = 10 m/s 2
Te kaha pōturi (F A ) = 8000 dyne = 8 x 10 3 dyne = (8 x 10 3 )(10 -5 N) = 8 x 10 -2 N = 0.08 Newton
Te mātotoru o te hinu kakara (ρ) = 0.8 gr/cm 3 = 800 kg/m 3
E hiahiatia ana: Te mātotoru o te koura
Rongoā:
Te taumaha o te koura i te rangi:
w = mg = ρ b V g —– Whārite 1
Ko V te rōrahi o te koura i roto i te hinu hinu.
Te kaha pōkarekare (F B ) e ōrite ana ki te taumaha o te koura i te rangi (w) tangohia te taumaha o te koura i roto i te hinu (w'):
w – w' = F A
w – w' = ρ f V g —– Whārite 2
Ko V te rōrahi o te koura i roto i te hinu hinu.
Ka taea te tuhi anō i ngā whārite e rua i runga ake nei ki raro nei:
Ko te whakautu tika ko C.
- He aha te mātāpono taketake kei muri i te kaha pōrewarewa?
- WhakautuKo te mātāpono matua o te kaha pōturi ko te Mātāpono a Ākirīmete. E kī ana ko te mea e totohu ana ki roto i te wai ka pāngia e te kaha whakarunga e te kaha pōturi e kiia nei ko te kaha pōturi, he rite te rahi ki te taumaha o te wai kua nekehia e te mea.
- He aha i māmā ake ai te āhua o tētahi mea ina rukuhia ki te wai?
- WhakautuIna rukuhia tētahi mea ki te wai, ka nekehia e ia tētahi rahinga wai. Ka puta he kaha pōrewarewa ki runga i te mea nā te taumaha o tēnei wai kua nekehia, ā, ka ārai i tētahi wāhanga o te taumaha o te mea, ka māmā ake te āhua.
- Mena ka mānu tetahi mea i runga i te wai, ka pēhea te whakataurite o te taumaha o te mea ki te kaha pōrewarewa e pā ana ki runga?
- WhakautuKi te mānu tetahi mea, ko te kaha pōturi e pā ana ki runga ka rite ki te taumaha o te mea. Koia te take e noho taurite ai te mea me te kore e totohu, e ara ake rānei.
- Ka pā te kaha pōrewarewa ki ngā mea i te rangi?
- WhakautuAe, ka pā te kaha pōrewarewa ki ngā mea i roto i tētahi wai, tae atu ki te hau. Heoi, nā te mea he iti ake te mātotoru o te hau i ngā wai pērā i te wai, he iti ake te kaha pōrewarewa i roto i te hau, ā, he iti noa iho te kaha mō ngā mea o ia rā.
- He aha i totohu ai ētahi mea ki te wai, ko ētahi e mānu ana?
- WhakautuKo te totohu, te mānu rānei o tētahi mea, e whakawhirinaki ana ki te whanaungatanga i waenga i tōna taumaha me te kaha pōrewarewa. Mena he nui ake te kaha pōrewarewa (nā te wai i nekehia) i te taumaha o te mea, ka mānu. Mena he nui ake te taumaha, ka totohu.
- Mehemea ka tangohia e koe tētahi pōro whakarewa tuwhera me tētahi pōro whakarewa totoka, he rite te rahi me te rauemi, ka rumakina ki te wai, ko tēhea te mea ka nui ake te kaha o te pōro?
- WhakautuKo te kaha pōrewarewa e whakawhirinaki ana ki te rōrahi o te wai kua nekehia, kaua ki te taumaha o te mea. Nā te mea he ōrite te rōrahi o te wai e nekehia ana e ngā pōro e rua, ka ōrite te kaha pōrewarewa e pā ana ki a rāua.
- He aha i mānu ai ngā kaipuke i hangaia ki te maitai, he nui ake te kikī i te wai?
- WhakautuHe nui ngā āputaputa o roto o ngā kaipuke, ko te tikanga he iti iho te matotoru toharite i te matotoru o te wai. Ka puta he kaha pōrewarewa i te wai e nekehia ana e te kaipuke, ka taea ai e ia te tautoko i te taumaha o te kaipuke, kia mānu ai.
- Ki te panaia e koe tētahi pōro e mānu ana ki roto i te wai kia hohonu ake, kātahi ka tukuna, he aha ka tupu?
- WhakautuKi te pana koe i tētahi pōro e mānu ana ki roto i te wai, ka whakanuia e koe te rahinga o te wai e nekehia ana e ia, ka whakanuia ai te kaha pōrewarewa. Ina tukuna e koe, ka panaia e te kaha pōrewarewa kua piki ake ki runga kia hoki rā anō ki tōna tūranga taurite.
- Ka ahatia te kaha pōrewarewa o tētahi mea i roto i te wai māori ki te wai tote mēnā ka nekehia mai i te wai māori ki te wai tote?
- WhakautuHe nui ake te kikī o te wai tote i te wai māori. Nō reira, mō te rahinga kotahi kua nekehia, ka nui ake te kaha pōrewarewa i roto i te wai tote i te wai māori. Nō reira, tera pea ka pōrewarewa te mea i roto i te wai tote ki runga ake i te wai māori.
- Ka taea e tētahi mea te noho pūmau i tētahi aronga (hei tauira, poutū) engari kāore e pumau i tētahi atu aronga (hei tauira, whakapae) i a ia e mānu ana i roto i te wai?
- WhakautuĀe, ko te pumau o tētahi mea e mānu ana e whakawhirinaki ana ki te tohatoha o tōna taumaha e pā ana ki te kaha e pōrewarewa ana. Mena kei runga tonu te pokapū o te kaha taumaha i te pokapū o te pōrewarewa, ka pumau te mea. Heoi, ki te whakarerekētia te aronga, ka rerekē pea te whanaungatanga i waenga i ngā pokapū, ka hua ake he kore pumau i taua aronga.
