Mana – ngā raruraru me ngā otinga

Ko te mana te tere o te mahi i roto i tētahi wā kua whakaritea. I roto i te pāngarau, ko te mana te ōwehenga mahi/wā.

P = W/t

Whakaahuatanga: P = mana (Joule/hēkona = Watt), W = mahi (Joule), t = wā (hēkona)

I runga i tēnei whārite, ka taea te whakatau ko te nui ake o te tere mahi, ko te nui ake o te mana. I tētahi atu taha, ko te iti ake o te tere mahi, ko te iti ake o te mana. Ko te tere mahi e pā ana ki te tere o te mahi.

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He tauine tauine te mana. Ko te waeine SI mō te mana ko te Joule/hēkona. Ko te Joule/hēkona = Watt (i whakarapopototia ko W), i tapaina pērā hei whakanui i a James Watt. Ko te waeine emepaea o Peretānia mō te mana ko te foot-pauna ia hekona.

He iti rawa tēnei waeine mō ngā mahi whaihua, nō reira ka whakamahia te waeine nui ake, arā, te hōihopa (arā, te hp). Kotahi hōihopa = 550 putu-pauna ia hekona = 764 Watts = ¾ kilowatt.

Ka taea hoki te whakaatu i te nui o te mahi i roto i ngā waeine mana x wā, hei tauira, kilowatt-hāora, kWh rānei. Ko te kotahi kWh e pā ana ki te mahi i mahia i te tere pumau o te 1 kiloWatt mō te haora kotahi.

1. E oma ana tētahi tangata 50-kg i ngā arawhata, 10 mita te teitei ⁱ roto i te 2 meneti. Ko te tere o te kaha ā -papa (g) he 10 m/ s2 . Tātaihia te mana.

Mōhiotia:

Taumaha (m) = 50 kg

Teitei (h) = 10 mita

Te whakaterenga nā te kaha ā-papa (g) = 10 m/s ²

Wā poto (t) = 2 meneti = 2 (60) = 120 hēkona s

E hiahiatia ana : Mana (P)

Rongoā:

Tātai o te mana:

P = W / t

P = mana , W = mahi , t = wā

Tātai Mahi:

W = F s = wh = mgh

W = mahi , F = kaha , w = taumaha , d = nekehanga , h = teitei , m = papatipu, g = whakaterenga nā te kaha ā-papatipu

W = mgh = (50)(10)(10) = 5000 Joule.

P = W / t = 5000 / 120 = 41.7 Joules/se c i runga i te d.

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2. Tātaihia te mana e hiahiatia ana mō tētahi tangata 60-kg te taumaha e piki ana i tētahi rākau e 5 mita te teitei i roto i te 10 hēkona. Ko te whakaterenga nā te kaha ā-papa he 10 m/ ^s².

Mōhiotia:

Taumaha (m) = 60 kg

Teitei (h) = 5 mita s

Te whakaterenga nā te kaha ā-papa (g) = 10 m/s ²

Wā wā (t) = 10 hēkona

E hiahiatia ana : Mana

Rongoā:

Mahi:

W = mgh = (60)(10)(5) = 3000 Joule

Mana:

P = W / t = 3000 / 10 = 300 Joules/se te āhua.

3. He kōmeke hurihuri, he 300 watts te kaha, ā, e 5 meneti te roa o te wā e hurihuri ana i ngā rauna e 5. Ko te kaha e whakamahia ana e ia ko….

A. 15 kJ

B. 75 kJ

C. 90 kJ

D. 450 kJ

Mōhiotia:

Mana (P) = 300 Watts = 300 Joules/hēkona

Wā (T) = 5 meneti = 5 (60 hēkona) = 300 hēkona

Te maha o ngā hurihanga = 5

E hiahiatia ana: Pūngao i whakamahia e te pukuhohe hurihuri

Rongoā:

Mana - ngā raruraru me ngā otinga

Ko te whakautu tika ko D.

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