Mienzaniso mina yemibvunzo pamusoro pekushandiswa kwemitemo yaNewton pakufamba kwakatwasuka kwechikwidzo kana chiridzi
1. Munhu ane huremu hwe50 kg ari muelevator. Kukurumidza kunokonzerwa negiravhiti = 10 m/s2Sarudza hukuru hwesimba rakajairika rinoitwa nepasi remuchinda pamunhu kana:
(a) elevator isina ruzha
(b) elevator inodzika pasi nespeed isingachinji
(c) elevator inokwira kumusoro nekumhanya kwe5 m/s2
(d) elevator inodzika pasi nekumhanya kwe5 m/s2
(e) elevator yekudonha yakasununguka
Kukurukurirana
Zvinozivikanwa :
Huremu hwemunhu (m) = 50 kg
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s2
Huremu hwemunhu (w) = mg = (50)(10) = 500 Newtons
Jawab :
(a) elevator isina ruzha
Elevator iri pazororo, hapana kumhanyisa (a = 0)
Simba rinonangidzirwa kumusoro rakanaka, simba rinonangidzirwa pasi harina kunaka.
(b) elevator inodzika pasi nespeed isingachinji
Elevator inofamba nekumhanya kwakafanana, hapana kumhanyisa (a = 0)
Simba rinonangidzirwa kumusoro rakanaka, simba rinonangidzirwa pasi harina kunaka.
(c) elevator inokwira kumusoro nekumhanya kwe5 m/s2
Elevator inokwira kumusoro nekumhanya (a) kwe5 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
N – w = ma
N = w + ma
N = 500 + (50)(5)
N = 500 + 250
N = 750 Newton
Hukuru hwesimba rakajairika (N) hwakaenzana nehuremu (w), saka kana elevator ikakwira mudenga, muviri wemunhu unonzwa kurema. Nemamwe mashoko, kana elevator ikakwira mudenga, huremu hwemunhu hunoonekwa hunokura. Kana munhu akamira pachikero, kana elevator ikakwira mudenga, chikero chinoratidza kuti huremu hwemunhu hwakakura.
(d) elevator inodzika pasi nekumhanya kwe5 m/s2
Elevator inodzika pasi nekumhanya (a) kwe5 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
w – N = ma
N = w – ma
N = 500 – (50)(5)
N = 500 – 250
N = 250 Newton
Erevheta painodzika, muviri wemunhu unonzwa wakareruka. Nemamwe mashoko, erevheta painodzika, huremu hwemunhu hunoonekwa hunowedzera. Dai munhu akamira pachikero, erevheta painodzika, chikero chacho chinoratidza huremu hwakaderera.
(e) elevator yekudonha yakasununguka
Elevator inodonha yakasununguka zvinoreva kuti elevator inofamba ichidzika pasi, uko kumhanyisa kweelevator (a) = kukurumidza kwegiravhiti (g). Semuenzaniso, g = 10 m/s2 ipapo a = 10 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
w – N = ma
N = w – ma
N = 500 – (50)(10)
N = 500 – 500
N = 0
Kana elevator iri mu free fall, huremu hwemunhu hwacho hunenge huri zero. Nemamwe mashoko, munhu wacho aizviona seasina huremu. Kana munhu wacho akamira pachikero, elevator painofamba ichidzika, chikero chacho chinoratidza kuti huremu hwake ndi zero. Mamiriro aya akafanana nekuva munzvimbo isina simba rinokwevera pasi.
2. Sarudza hukuru hwesimba rekumanikidza patambo yekutsigira inosimudza ine huremu hwe2000 kg, kana:
(a) elevator isina ruzha
(b) elevator inodzika pasi nekumhanya kwe5 m/s2
(c) elevator inokwira kumusoro nekumhanya kwe5 m/s2
(d) elevator yekudonha yakasununguka
Fungidzira kuti kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s2
Kukurukurirana
Zvinozivikanwa :
Huremu hwekusimudza (m) = 2000 kg
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s2
Kurema kwekusimudza (w) = mg = (2000)(10) = 20.000 Newtons
Jawab :
(a) elevator isina ruzha
Elevator iri pazororo, hapana kumhanyisa (a = 0)
Simba rinonangidzirwa kumusoro rakanaka, simba rinonangidzirwa pasi harina kunaka.
Kana chikwidzo chichiripo, simba rekumanikidza patambo (T) = huremu hwechikwidzo (w) = 20.000 Newtons
(b) elevator inodzika pasi nekumhanya kwe5 m/s2
Elevator inodzika pasi nekumhanya (a) kwe5 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
w – T = ma
T = w – ma
T = 20.000 – (2000)(5)
T = 20.000 - 10.000
T = 10.000 Newton
Kana elevator yadzika pasi, simba rekumanikidza patambo (T) rinova diki pane kana elevator yakamira.
(c) elevator inokwira kumusoro nekumhanya kwe5 m/s2
Elevator inokwira kumusoro nekumhanya (a) kwe5 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
T – w = ma
T = w + ma
T = 20.000 + (2000)(5)
T = 20.000 + 10.000
T = 30.000 Newton
Kana elevator ikakwira kumusoro, simba rekumanikidza patambo (T) rinokura kupfuura kana elevator isingamire.
(d) elevator yekudonha yakasununguka
Elevator inodonha yakasununguka zvinoreva kuti elevator inofamba ichidzika pasi, uko kumhanyisa kweelevator (a) = kukurumidza kwegiravhiti (g). Semuenzaniso, g = 10 m/s2 ipapo a = 10 m/s2
Simba riri munzira imwe chete nekufamba kwechikwidzo rakanaka, simba riri munzira inopesana nekufamba kwechikwidzo harina kunaka.
w – T = ma
T = w – ma
T = 20.000 – (2000)(10)
T = 20.000 - 20.000
T = 0
Kana elevator iri mukudonha kwakasununguka, kumanikidzwa kwetambo (T) kunova zero. Nekuti kumanikidzwa kwetambo kwakaenzana nehuremu hweelevator, kana kumanikidzwa kwetambo kuri zero, huremu hweelevator hunoitawo kunge zero. Mamiriro aya akafanana neapo chinhu chiri mugomba regiravhiti kana nzvimbo isina simba regiravhiti.
[Chirungu: Kushandiswa kwemutemo waNewton wekufamba muelevator ]
3. Munhu ane huremu hwe60 kg ari muelevator iri kufamba ichidzika pasi nekumhanya kwe3 ms -2 . Kana kumhanya nekuda kwesimba rinokwevera pasi kuri 10 ms -2 , saka simba rakajairika rinoitwa neelevator pasi pamunhu...
A. 180 N
B. 200 N
C. 340 N
D. 420 N
E. 600 N
Kukurukurirana
Zvinozivikanwa kuti:
Huremu (m) = 60 kg
Kukurumidza kwemunhu neelevator (a) = 3 m/s2
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s2
Simba regiravhiti (w) = mg = (60)(10) = 600 Newtons
Akabvunzwa: simba rakajairika (N)
Mhinduro:
Kune masimba maviri anoshanda pamunhu ari muelevator, anoti simba rinokwevera pasi (w) uye simba rakajairika rinoitwa nepasi reelevator pamunhu (N). Kune mavector quantities matatu, anoti simba rinokwevera pasi, simba rakajairika, uye kuwedzera simba reelevator, uko simba rinokwevera pasi rinonangidzirwa pasi, simba rakajairika rinonangidzirwa kumusoro, uye kuwedzera simba reelevator kunonangidzirwa pasi. Vector quantity inosarudzwa kuti ive nechiratidzo chakanaka uye vector quantity inosarudzwa kuti ive nechiratidzo chisina kunaka.
∑F = ma
w – N = (60)(3)
600 – N = 180
N = 600 – 180
N = 420 Newton
Mhinduro chaiyo ndiD.
4. Reza, ane huremu hwe40 kg, ari muelevator iri kufamba ichikwira mudenga. Kana simba repasi reelevator patsoka dzaReza riri 520 N uye kumhanya kunokonzerwa negravity kuri 10 ms -2 , saka kumhanya kweelevator kuri...
A. 1,0 ms-2
B. 1,5 ms-2
C. 2,0 ms-2
D. 2,5 ms-2
E. 3,0 ms-2
Kukurukurirana
Zvinozivikanwa kuti:
Huremu (m) = 40 kg
Simba rakajairika (N) = 520 N
Kukurumidza kunokonzerwa negiravhiti (g) = 10 m/s2
Simba regiravhiti (w) = mg = (40)(10) = 400 N
Akabvunzwa: Kukurumidza kwerifiti
Mhinduro:
∑F = ma
400 – 520 = (40)(a)
-120 = (40)(a)
a = -120/40
a = -3 m/s2
Kumhanya kweelevator ndeye 3 m/s2Chiratidzo chekuramba chinoreva kuti lifti iri kukwira kumusoro.
Mhinduro chaiyo ndiE.
Kwakabva mubvunzo:
Mibvunzo yeNational Examination Physics yeChikoro Chesekondari/Chikoro Chepamusoro Chebasa
