Te Momentum – ngā raruraru me ngā otinga

1. Ka neke te pōro 0.5-kg i te 2 m/s. Kātahi ka pāngia te pōro e te kaha F i te ritenga kē atu o te ahunga o te pōro , nō reira ka hurihia te tere o te pōro ki te 6 m/s . Ka pā te pōro ki te kaiwhiu mō te 0.01 hēkona, he aha te huringa o te nekehanga o te pōro?

Mōhiotia:

Taumaha o te pōro (m) = 0.5 kg

Te tere tīmatanga (v _o ) = 2 m/s

Te tere whakamutunga (vt ₎ = -6 m/s

Wā wā (t) = 0.01 hēkona

E hiahiatia ana: Te huringa o te nekehanga

Rongoā:

∆p = mv _t – mv _o = m (v _t – v _o )

∆p = (0.5 kg)(- 6 m/s – 2 m/s)

∆p = (0.5 kg)(-8)

∆p = 4 kg m/s

2. E neke ana tētahi mea 100-karamu i te 5 m/s. Ka mahi te kaha F mō te 0.2 hēkona hei aukati i te mea. Tātaihia te rahi o te kaha F.

Mōhiotia:

Taumaha o te mea (m) = 100 karamu = 100/1000 = 0.1 kg

Te tere tīmatanga (v _o ) = 5 m/s

Te tere whakamutunga (vt ₎ = 0

Wā wā (Δt) = 0.2 hēkona

E hiahiatia ana: Te rahi o te kaha F

Rongoā:

I = ΔP

F (Δt) = m (vt _– v _o )

F (0.2) = 0.1 (0 – 5)

F (0.2) = 0.1 (– 5)

F (0.2) = -0,5

F = -0,5 / 0.2

F = -2.5 N

Te rahi o te kaha F = 2.5 Newton. Ko te tohu tango e tohu ana i te ahunga o te kaha e anga ke ana ki te ahunga o te mea.

3. Ka taka noa tetahi pōro 100-karamu mai i te teitei o te 20 cm me te kore he tere tīmatanga, kātahi ka pā te pōro ki te papa. I muri i te tukinga, ka whakaatahia te pōro ki runga (ko te tere o te kaha ā-papa he 10 ms ^-2 ). He aha te panoni o te nekehanga o te pōro?

Mōhiotia:

Taumaha o te pōro (m) = 100 karamu = 0.1 kg

Teitei (h) = 20 cm = 0.2 mita

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

Te tere o te pōro i muri i te pānga ki te papa (vt ₎ = 1 m/s

E hiahiatia ana: Te huringa o te nekehanga

Rongoā:

Te tere o te pōro i mua i te tukinga (v _o )

Tātaihia te tere o te pōro i mua i te tukinga mā te whakamahi i te whārite o te nekehanga hinga noa. E mōhiotia ana: te teitei o te pōro (h) = 0.2 mita, te whakaterenga nā te kaha ā-papa (g) = 10 m/s2 ^. E hiahiatia ana: te tere o te pōro ina pā ki te papa.

v ² = 2 gh

v ² = 2 (10)(0.2) = 4

v = √4 = -2 m/s

Ko te tohu tango e tohu ana ko te ahunga o te pōro i mua i te tukinga he ritenga ke ki te ahunga o te pōro i muri i te tukinga.

Te huringa o te nekehanga o te pōro (Δp)

Δp = mv _t – mv _o = m (v _t – v _o )

Δp = (0.1)(1 – (-2)) = (0.1)(1 + 2) = (0.1)(3) = 0.3 hēkona Newton

4. I te tīmatanga ka pahū tētahi mea kia rua ngā wāhanga, ko te ōwehenga o te 3: 2 . Ka whiua te wāhanga nui o te papatipu i te tere o te 20 m/s. He aha te tere o te wāhanga iti?

Mōhiotia:

Papatipu o te mea 1 i mua i te pahūtanga = m

Te tere o te mea 1 i mua i te pahūtanga = 0 (te mea e okioki ana)

Papatipu o te wāhanga nui ake i muri i te pahūtanga (m1 ₎ = 3m

Papatipu o te wāhanga iti i muri i te pahūtanga (m2 ₎ = 2m

Te tere o te wāhanga nui i muri i te pahūtanga (v ₁ ') = 20 m/s

E hiahiatia ana: Te tere o te wāhanga iti i muri i te pahūtanga (v ₂ ')

Rongoā:

Ko te whārite o te ture o te tiakitanga o te nekehanga:

m ₁ v ₁ = m ₁ v ₁ ' + m ₂ v ₂ '

(m)(0) = (3m)(20) + (2m) v ₂ '

0 = 60m + (2m) v ₂ '

60m = -2m v ₂ '

60 = -2 ki te ₂ '

v ₂ ' = -60/2

v ₂ ' = -30 m/s

Ko te tohu tango e tohu ana ko te ahunga o te wāhanga iti kei te ritenga ke i te ahunga o te wāhanga nui.

He aha te tere?
- whakahoki: Ko te nekehanga he rahinga whārite e tohu ana i te hua o te papatipu o tētahi mea me tōna tere. E tohu ana i te ahunga me te rahi o te nekehanga, ā, he maha ngā wā ka tohuhia e $p$ , kua tautuhia hei $p = m v$ .
He aha te rerekētanga o te nekehanga mai i te tere?
- whakahoki: Ahakoa he rahinga whārite e pā ana ki te nekehanga te nekehanga me te tere, ko te tere anake e whakaahua ana i te tere me te ahunga o te nekehanga o te mea, engari ko te nekehanga e whakaaro ana ki te papatipu me tōna tere o te mea. Mā te nekehanga ka ine i te uaua o te aukati i te mea e neke ana.
He aha te mātāpono o te tiakitanga o te nekehanga?
- whakahoki: E ai ki te mātāpono o te tiaki i te nekehanga, i roto i tētahi pūnaha motuhake, me ōrite te nekehanga katoa i mua i tētahi huihuinga (pēnei i te tukinga) ki te nekehanga katoa i muri i te huihuinga, ki te kore he kaha o waho e pā ki te pūnaha.
He aha te hononga o te hihiri ki te tere?
- whakahoki: Ko te impulse te huringa o te nekehanga o tētahi mea ina pāngia he kaha mō tētahi wā motuhake. Ka homai tēnei e te hua o te kaha me te wā e mahi ana, ā, he ōrite ki te huringa o te nekehanga: $Tuhinga = F \times Δ t = Δ p$ .
He aha ngā pēke hau i roto i ngā waka e āwhina ai ki te ārai i ngā whara i te wā tukinga?
- whakahoki: Ka whakanuia e ngā pēke hau te roa o te pānga o te kaha ki te kainoho i te wā tukinga. Ka whakaitihia e tēnei te kaha toharite e pā ana ki te kainoho. Mā te hononga nekehanga-whakaohooho, mā te hora i te huringa o te nekehanga mō te wā roa ka whakaitihia te kaha, ka āwhina i te ārai i ngā whara.
He aha te rerekētanga i waenga i ngā tukinga rapa me ngā tukinga kore rapa e pā ana ki te nekehanga me te pūngao nekeneke?
- whakahoki: I roto i ngā tukinga rapa me ngā tukinga kore-rapa, ka tiakina te nekehanga. Heoi, i roto i ngā tukinga rapa, ka tiakina hoki te pūngao nekeneke katoa, engari i roto i ngā tukinga kore-rapa, kāore.
Me pēhea te tiaki i te nekehanga o te hoki whakamuri o te pū ina pupuhihia?
- whakahoki: Ina pupuhihia he pū, ka neke whakamua te matā me tētahi nekehanga motuhake. Hei pupuri i te nekehanga i roto i te pūnaha motuhake (ki te whakaaro he iti noa ngā kaha o waho pēnei i te ātete hau), me neke whakamuri te pū me tētahi nekehanga ōrite, rerekē hoki. E mōhiotia ana tēnei nekehanga whakamuri ko te hoki whakamuri.
He aha i taka ai ngā mea o ngā taumaha rerekē i te tere kotahi i roto i te korehau engari he rerekē ngā wā?
- whakahoki: I roto i te korehau, he rite tonu te whakaterenga nā te kaha ā-papatipu mō ngā mea katoa ahakoa te taumaha. Nō reira, he rite tonu te tere o te hekenga o ngā taumaha rerekē. Heoi, ko te nekehanga e whakawhirinaki ana ki te tere me te taumaha. Nā te mea he $p = m v$ , ka rerekē te tere o ngā mea e rua he rerekē ō rāua taumaha engari he ōrite te tere.
He aha te hononga o te ture tuatoru a Newton ki te tiakitanga o te nekehanga?
- whakahoki: E ai ki te ture tuatoru a Newton, mō ia mahi, he tauhohenga ōrite, he tauhohenga rerekē. Ina taunekeneke ngā mea e rua, ka whakamahia e rāua ngā kaha ōrite, he tauhohenga rerekē ki a rāua anō mō te wā kotahi, arā, ka pāngia rāua e ngā huringa ōrite, he tauhohenga rerekē o te nekehanga. Ko te hua o tēnei, ko te tapeke o te nekehanga i mua i te taunekeneke he ōrite ki te tapeke o te nekehanga i muri mai, ā, ka tiakina te nekehanga.
He aha i māmā ake ai te whakamutu i tētahi pahikara e neke ana i tētahi motuka e neke ana, ahakoa he rite tonu te tere?

whakahoki: Ahakoa he rite te tere o te pahikara me te motuka, he rerekē te kaha o te nekehanga nā te rerekētanga o ō rāua taumaha. Ka whakawhirinaki te kaha o te nekehanga ki te tere me te taumaha. He nui ake te kaha o te motuka i te pahikara, ā, he rite tonu te tere. Nō reira, me nui ake te kaha (te huringa rānei o te kaha) hei whakamutu i te motuka ki te whakataurite ki te pahikara.