Te kaha hikohiko – ngā raruraru me ngā otinga
1. Mena ko te kaha hiko pūmau he 144 N, he aha te tawhiti i waenga i ngā utu e rua … (1 μC = 10 -6 C me k = 9.10 9 Nm 2 .C -2 )
Mōhiotia:
Te kaha hiko (F 12 ) = 144 N
Utu 1 (q 1 ) = 10 μC = 10 x 10 -6 C
Utu 2 (q 2 ) = 4 μC = 4 x 10 -6 C
Pūmau (k) = 9 x 10 9 Nm 2 .C -2
C = Coulomb, N = Newton, m = mita
E hiahiatia ana: Te tawhiti i waenga i ngā utu e rua (r)
Rongoā:
Te whārite o te ture a Coulomb :
F = te kaha hiko pūmau, k = te pūmau o Coulomb, q = te utu hiko, r = te tawhiti i waenga i ngā utu e rua
Te tawhiti i waenganui i ngā utu e rua (r) = 5 x 10 -2 mita = 5 x 10 -2 x 10 2 henimita = 5 henimita.
2. E rua ngā utu e wehea ana e te tawhiti o r . Mena he 3.6 N te kaha hiko pumau, he aha te tawhiti i waenganui i ngā utu e rua ( 1 μC = 10 -6 C me k = 9.10 9 Nm².C -2 )
Mōhiotia:
Te kaha hiko (F 12 ) = 3.6 N
Utu 1 (q 1 ) = 9 μC = 9 x 10 -6 C
Utu 2 (q 2 ) = 4 μC = 4 x 10 -6 C
Te pūmau o Coulomb (k) = 9 x 10 9 Nm 2 .C -2
C = Coulomb, N = Newton, m = mita
E hiahiatia ana: Te tawhiti i waenga i ngā utu e rua (r)
Rongoā:
Te tawhiti i waenganui i ngā utu e rua (r) = 0.3 m = 0.3 x 100 cm = 30 cm.
3. Ngā utu pūwāhi e toru e whakaaturia ana i te pikitia i raro nei. He aha te rahi o te kaha hiko pūmau i te pūwāhi A (k = 9.10 9 Nm 2 .C -2 ; 1 μ = 10 -6 )
Mōhiotia:
Akona A (qA) = -2 μC = -2 x 10-6 C
Utu B (q B ) = 8 μC = 8 x 10 -6 C
Utu C (q C ) = 4,5 μC = 4,5 x 10 -6 C
Ko te pūmau o Coulomb (k) = 9 x 10 9 Nm 2 .C -2
Te tawhiti i waenganui i ngā utu A me B (r AB ) = 4 cm = 4 x 10 -2 m
Te tawhiti i waenganui i ngā utu A me C (r AC ) = 3 cm = 3 x 10 -2 m
C = Coulomb, N = Newton, m = mita
E hiahiatia ana: Te kaha hiko pūmau i te pūwāhi A
Rongoā:
Te whārite o te ture a Coulomb:
F = te kaha hiko pūmau , k = te pūmau o Coulomb , q = te utu hiko , r = te tawhiti i waenga i ngā utu e rua
Ko te kaha hiko pūmau i te pūwāhi A:
4. Ngā utunga-toru e whakaaturia ana i te pikitia i raro nei. He aha te rahi o te kaha Coulomb i pā ki te Utunga B (k = 9.10 9 Nm 2 .C -2 ; 1 μC = 10 -6 C ).
Mōhiotia:
q A = 10 µC = 10 x 10 -6 C = 10 -5 Coulombs
q B = 10 µC = 10 x 10 -6 = 10 -5 Ngā Coulomb
q C = 20 µC = 20 x 10 -6 = 2 x 10 -5 Ngā Coulomb
r AB = 0.1 mita = 10 -1 m
r BC = 0.1 mita = 10 -1 m
k = 9 x 10 9 Nm 2 C −2
E hiahiatia ana: Te kaha Coulomb i pā ki te Utu B
Rongoā:
E rua ngā kaha coulomb e pā ana ki te utu B, ko te kaha Coulomb i waenganui i ngā utu A me B (F AB ) me te kaha Coulomb i waenganui i ngā utu B me C (F BC ). Ko te kaha Coulomb e pāngia ana e te utu B ko te kaha kupenga o F AB me F BC.
Te kaha Coulomb i waenganui i ngā utu A me B:
I hainatia e te utunga A he pai, ā, i hainatia hoki e te utunga B he pai, kia tohu ai a F AB ki te utunga C.
Te kaha Coulomb i waenganui i ngā utu B me C:
I hainatia te tohu pai e te utu B, ā, i hainatia hoki te tohu pai e te utu C, kia tohu ai a F BC ki te utu A.
Te kaha Coulomb e pāngia ana e te utu B:
F B = F BC – F AB = 180 – 90 = 90 N
Ko te kaha Coulomb e pāngia ana e te utu B (F B ) he 90 Newtons. Ko te ahunga o F B he rite tonu ki te ahunga o F BC e tohu ana ki te utu A.
5. Tātaihia te rahi me te ahunga o te kaha Coulomb i runga i te utu B ( k = 9 x 109 Nm2C −2 , 1 μC = 10−6C ).
Mōhiotia:
Utu A (q A ) = +Q
Utu B (q B ) = -2Q
Utu C (q C ) = -Q
Te tawhiti i waenganui i ngā utu A me B (r AB ) = r
Te tawhiti i waenganui i ngā utu B me C (r BC ) = 2r
k = 9 x 10 9 Nm 2 C −2
E hiahiatia ana: Te rahi me te ahunga o te kaha Coulomb i runga i te utu B
Rongoā:
Te kaha Coulomb i waenganui i ngā utu A me B:
He pai te utu A, he kino te utu B, nō reira ka tohu te ahunga o F AB ki te utu A.
Te kaha Coulomb i waenganui i te utu B me te utu C:
He kino te utu B, he kino hoki te utu C, nō reira ka tohu te ahunga o F BC ki te utu A.
Te mahi a te kaha kupenga ki te utu B:
F = FAB +FBC = 2 k Q2/r2 + 0.5 k Q2/r2 = 2.5 k Q2/r2 = 2.5 k Q2 r-2
Ka anga te ahunga o te kaha ki te utu A, ki maui rānei.
