1. Ka taka noa tetahi tinana 1-kg mai i te tūnga, mai i te teitei o te 80 m. Ko te tere o te kaha ā-papa he 10 m/s² . He aha te pūngao nekeneke ina pā te tinana ki te whenua.
Mōhiotia:
Taumaha (m) = 1 kg
Teitei (h) = 80 m
Te whakaterenga nā te kaha ā-papa (g) = 10 m/s 2
E hiahiatia ana: te pūngao nekeneke ina pā te tinana ki te whenua
Rongoā:
Ko te pūngao ā-pūkaha tīmatanga (ME o ) = te pūngao pūmanawa ā-papa (PE)
M E o = P E = mgh = (1)(10)(80) = 800 Joule
Ko te pūngao miihini whakamutunga (M E t ) = te pūngao nekeneke (K E )
Te mātāpono o te tiaki i te pūngao miihini :
ME o = ME t
P E = K E
800 = K E
Ko te pūngao nekeneke whakamutunga ko 800 Joules.
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2. Ka taka noa tētahi tinana 4-kg te taumaha mai i te tūnga, mai i te teitei o te 10 m. Ko te tere o te kaha ā-papa he 10 ms –2 . He aha te pūngao nekeneke me te tere i te 5 mita i runga ake i te whenua.
Mōhiotia:
Ko te panonitanga o te teitei (h) = 10 – 5 = 5 mita s
Taumaha (m) = 4 kg
Te whakaterenga nā te kaha ā-papa (g) = 10 m/s 2
E hiahiatia ana: Pūngao nekeneke i te 5 mita i runga ake i te whenua me te tere i te 5 mita i runga ake i te whenua
Rongoā:
(a) Pūngao nekeneke i te 5 mita i runga ake i te whenua
Ko te pūngao miihini tīmatanga (M E o ) = te pūngao pūmanawa ā-papa (P E )
M E o = P E = mgh = (4)(10)(5) = 200 Joule
Ko te pūngao miihini whakamutunga (EM t ) = te pūngao nekeneke (EK)
M E t = K E
Ko te mātāpono o te tiaki i te pūngao ā-pūkaha e kī ana ko te pūngao ā-pūkaha tīmatanga = te pūngao ā-pūkaha whakamutunga.
ME o = ME t
200 = K E
Ko te pūngao nekeneke i te 5 mita i runga ake i te whenua he 200 Joules.
(b) te tere i te 5 mita i runga ake i te whenua
Ko te pūngao miihini tīmatanga (M E o ) = te pūngao miihini whakamutunga (M E t )
P E = K E
200 = ½ mv 2
2(200) / 4 = v 2
100 = v 2
v = √100
v = 10 m/s
Ko te tere o te tinana i te 5 mita i runga ake i te whenua he 10 m/s.
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3. Ka taka noa te māngo mai i te tūnga, mai i te teitei o te 2 mita. Ko te tere o te kaha ā-papa he 10 ms –2 . Tātaihia te tere o te māngo ina pā ki te whenua.
Mōhiotia:
Teitei (h) = 2 mita s
Te whakaterenga nā te kaha ā-papa (g) = 10 m/s 2
E hiahiatia ana: te tere o te māngo ina pā ki te whenua.
Rongoā:
Ko te pūngao miihini tīmatanga (M E o ) = te pūngao pūmanawa ā-papa (P E )
M E = P E = mgh = m (10)(2) = 20 m
Ko te pūngao miihini whakamutunga (M E t ) = te pūngao nekeneke (K E )
M E t = K E = ½ mv 2
Ko te mātāpono o te tiaki i te pūngao ā-pūkaha e kī ana ko te pūngao ā-pūkaha tīmatanga = te pūngao ā-pūkaha whakamutunga.
ME o = ME t
20 m = ½ mv 2
20 = ½ v 2
2(20) = v2
40 = v 2
v = √40 = √(4)(10) = 2√10 m/ s
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- Ngā raruraru me ngā otinga mō te mahi i mahia mā te kaha
- Ngā raruraru me ngā otinga mō te pūngao mahi-nekeneke
- Ngā raruraru me ngā otinga o ngā mātāpono mahi-pūngao miihini
- Ngā raruraru me ngā otinga o te pūngao pūmanawa ā-papa
- Te pūngao pūmanawa o ngā raruraru me ngā otinga o te puna rapa
- Ngā raruraru hiko me ngā otinga
- Te whakamahinga o te tiakitanga o te pūngao miihini mō te nekehanga hinga noa
- Te whakamahinga o te tiakitanga o te pūngao miihini mō te nekehanga ki runga, ki raro hoki i te nekehanga hinga noa.
- Te whakamahinga o te tiakitanga o te pūngao miihini mō te nekehanga i runga i te mata piko
- Te whakamahinga o te tiakitanga o te pūngao miihini mō te nekehanga i runga i te paparangi piko
- Te whakamahinga o te tiaki i te pūngao miihini mō te nekehanga pere