Zitsanzo za mafunso okhudza ntchito ndi mphamvu

Zitsanzo 16 za Mafunso Okhudza Ntchito ndi Mphamvu

Chiphunzitso Mphamvu ya Kinetic ya Ntchito

1. Mphamvu yosalekeza ya 60 N imagwira ntchito kwa masekondi 12 pa chinthu cholemera makilogalamu 10. Chinthucho

Ili ndi liwiro loyambirira la 6 m/sec mbali imodzi ndi mphamvu.

(1) Ntchito yomwe yachitika pa chinthucho ndi ma joules 30.240

(2) Mphamvu yomaliza ya kinetic ya chinthucho ndi ma joules 30.240.

(3) Mphamvu yopangidwa ndi 2.520 watts

(4) Kuwonjezeka kwa mphamvu ya kinetic ya chinthucho ndi ma joules 180.

Chiganizo cholondola ndi chakuti…

A. 1, 2 ndi 3

B. 1 ndi 3

C. 1 ndi 4

D. 4 okha

E. zonse ndi zolondola

Zokambirana

Amadziwika kuti:

Mphamvu (F) = 60 N

Nthawi yopuma (t) = masekondi 12

Kulemera kwa chinthu (m) = 10 kg

Liwiro loyambirira (v _o ) = 6 m/s

Funso: Ndi chiganizo chiti chomwe chili cholondola?

Yankho:

Kufulumizitsa chinthu:

∑ F = ma

60 = 10 a

a = 60 / 10 = 6 m/s ²

Liwiro lomaliza:

v _t = vo ₊ pa

v _t = 6 + (6)(12)

v _t = 6 + 72

v _t = 78 m/s

Mtunda woyenda mu masekondi 12:

s = vot ₊ 1/2 pa ²

s = (6)(12) + 1/2 (6)(12) ²

s = 72 + (3)(144)

s = 72 + 432

s = mamita 504

(1) Ntchito yatha

W = F s = (60)(504) = 30.240 Joules

(2) Mphamvu yomaliza ya kinetic ya chinthucho

EK = 1/2 mv _t ² = 1/2 (10) (78) ² = (5) (6084) = 30.420 Joules

(3) Mphamvu yopangidwa

P = W / t = 30.240 / 12 = 2.520 Joules/sekondi

(4) Kuwonjezeka kwa mphamvu ya kinetic

ΔEK = 1/2 mv _t ² – 1/2 mv _o ² = 1/2 m (v _t ² – v _o ² ) = 1/2 (10) (78 ² – 6 ² ) = 5 (6084 –36) = 5 (6048)

ΔEK = 30.240 Joule

Yankho lolondola ndi B.

2. Deta yokhudza kusintha kwa liwiro la chinthu chomwe chikuyenda molunjika yaperekedwa motere. Ntchito yayikulu kwambiri imachitika ndi nambala ya chinthu….

A. 1

B. 2

C. 3

D. 4

5

Zokambirana

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito:

Ntchito yonse = kusintha kwa mphamvu ya kinetic

Chiwerengero _chonse = ½ m (v _t ² – _vo ² )

Mabizinesi akuluakulu ndi awa:

W ₁ = ½ (8)(4 ² – 2 ² ) = (4)(16 – 4) = (4)(12) = 48 Ma Joules

W ₂ = ½ (8)(5 ² –3 ² ) = (4)(25 – 9) = (4)(16) = 64 Joules

W ₃ = ½ (10)(6 ² – 5 ² ) = (5)(36 – 25) = (5)(11) = 55 Ma Joules

W ₄ = ½ (10)(4 ² – 0 ² ) = (5)(16 – 0) = (5)(16) = 80 Ma Joules

W ₅ = ½ (20)(3 ² – 3 ² ) = (10)(9 – 9) = (10)(0) = 0 Ma Joules

Yankho lolondola ndi D.

3. Odi akuyendetsa galimoto yolemera makilogalamu 4000 pamsewu wowongoka pa liwiro la 25 m/s. Ataona kuchuluka kwa magalimoto patali, akuyendetsa galimotoyo kuti liwiro la galimotoyo lichepe nthawi zonse kufika pa 15 m/s. Ntchito yomwe gulu loyendetsa mabuleki limachita ndi….

A. 200 kJ

B. 300 kJ

C. 400 kJ

D. 700 kJ

E. 800 kJ

Zokambirana

Amadziwika kuti :

Kulemera kwa galimoto (m) = 4000 kg

Liwiro loyambirira la galimoto (v _o ) = 25 m/s

Liwiro lomaliza la galimoto (v _t ) = 15 m/s

Funso : Kodi mumagwira ntchito (W) pagalimoto?

Yankho :

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito:

Chiwerengero _chonse = ½ m (v _t ² – vo ₂ ⁾ = ½(4000)(15 ² -25 ² ) = (2000)(225-625) = (2000)(-400) = -800.000 Ma Joules = -800 ma Joules.

Yankho lolondola ndi E.

4. Mpira wolemera makilogalamu 0,1 umaponyedwa mopingasa pa liwiro la 6 m/s kuchokera padenga la nyumba yomwe ili ndi kutalika kwa mamita 5. Ngati kuthamanga chifukwa cha mphamvu yokoka pamalopo kuli 10 m/s ² , ndiye kuti mphamvu ya kinetic ya mpirawo pamtunda wa mamita 2 ndi….

A. 6,8 J

B. 4,8 J

C. 3,8 J

D. 3 J

E. 2 J

Zokambirana

Amadziwika kuti :

Kulemera (m) = 0,1 kg

Kusintha kwa kutalika (h) = 5 m – 2 m = mamita 3

Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ²

Funso : mphamvu ya kinetic (EK) pamtunda wa mamita awiri?

Yankho :

Njira ya mpira ndi monga momwe chithunzi chili pansipa chikusonyezera.

Kuyenda kwa parabolic monga momwe kwasonyezedwera pachithunzi pamwambapa ndi kuphatikiza kwa mayendedwe awiri omwe angasanthuledwe padera, pomwe kuyenda kolunjika kuli mu mawonekedwe a kuyenda kolunjika nthawi zonse ndipo kuyenda kolunjika kuli mu mawonekedwe a kuyenda kopanda kugwa.

Vutoli limathetsedwa pogwiritsa ntchito lamulo losunga mphamvu zamakanika, chifukwa chake timangoganizira za kuyenda molunjika mu mawonekedwe a kuyenda kopanda kugwa.

Chinthu chilichonse chomwe chimayenda mu free fall sichikhala ndi liwiro loyambirira (v _o = 0) kotero mphamvu yoyambirira ya kinetic ya chinthucho ndi zero (EK = ½ mv ² = 0). Kumbali inayi, chinthucho chimayamba kuyenda kuchokera kutalika kwa mamita 5 pamwamba pa nthaka kotero chinthucho chimakhala ndi mphamvu yokoka. Chifukwa chake mphamvu yoyambirira ya makina ya mpira ndi mphamvu yokoka. Mpira ukayamba kuyenda pansi, mphamvu yokoka ya mpira imasintha kukhala mphamvu yokoka. Mphamvu yokoka yomwe imasintha imapanga mphamvu yokoka pamene mpira ukusuntha kuchokera kutalika kwa mamita 5 pamwamba pa nthaka kupita kutalika kwa mamita 2 pamwamba pa nthaka ndi: EP = mgh = (0,1)(10)(3) = 3 Joules. Mpira ukakhala pamtunda wa mamita 2 pamwamba pa nthaka, mphamvu yokoka ya mpira ndi 3 Joules.

Yankho lolondola ndi D.

5. Galimoto yolemera tani imodzi imayamba kuchokera pamalo opumulira. Patapita kanthawi kochepa, liwiro lake ndi 5 m/s ^-1 . Kuchuluka kwa ntchito yomwe injini ya galimotoyo imachita ndi...

A. 1000 Joule

B. 2.500 Joule

C. 5.000 Joule

D. 12.500 Joule

E. 25.000 Joule

Zokambirana

Amadziwika kuti :

Kulemera (m) = tani imodzi = 1000 kg

Liwiro loyambirira (v _o ) = 0 (galimoto imayamba kuchokera pamene yapumula)

Liwiro lomaliza (v _t ) = 5 m/s

Funso : Kodi injini ya galimoto imagwira ntchito yochuluka bwanji (W)?

Yankho :

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito:

Chiwerengero _chonse = ½ m (v _t ² – _vo ² )

Ntchito zomwe injini ya galimoto imachita ndi izi:

Chiwerengero _chonse = ½ (1000)(5 ² – 0 ² ) = (500)(25 – 0) = (500)(25) = 12.500 Joules

Yankho lolondola ndi D.

6. Mpira wolemera magalamu 500 umaponyedwa molunjika mmwamba kuchokera pansi ndi liwiro loyambirira la 10 ms ^-2 . Ngati g = 10 ms ^-2 , ndiye kuti ntchito yokoka ya mpira ikafika kutalika kwake kwakukulu ndi...

A. 2,5 J

B. 5,0 J

C. 25 J

D. 50 J

E. 500 J

Zokambirana

Musanyalanyaze kukana kwa mpweya.

Amadziwika kuti :

Kulemera kwa mpira (m) = magalamu 500 = 0,5 kg

Liwiro loyambirira (v _o ) = 10 m/s ²

Liwiro lomaliza (v _t ) = 0. Pa kutalika kwakukulu, chinthucho chimakhala chili pampando kwa kanthawi chisanabwerere mmbuyo.

Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ²

Kufunidwa : Ntchito (W) yochitidwa ndi mphamvu yokoka ya mpira

Yankho :

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito :

Chiphunzitso cha mphamvu ya work-kinetic chimanena kuti ntchito yonse kapena khama lochitidwa ndi mphamvu yochokera pa chinthu ndi yofanana ndi kusintha kwa mphamvu ya kinetic ya chinthucho. Fomula ya chiphunzitso cha mphamvu ya work-kinetic ndi iyi:

W _chiwerengero = ΔEK = EK _t - EK _o

Chiwerengero _chonse = ½ mv _t ² – ½ mv _o ² = ½ m (v _t ² – _vo ² )

Zambiri:

EK _t = mphamvu yomaliza ya kinetic, EK _o = mphamvu yoyambirira ya kinetic, m = kulemera kwa chinthucho, v _t = liwiro lomaliza la chinthucho, v _o = liwiro loyambirira la chinthucho.

Khama lonse :

Ntchito yochitidwa ndi kulemera kwa mpira kuyambira nthawi yomwe mpira waponyedwa mpaka mpirawo utafika kutalika kwake kwakukulu ndi:

Chiwerengero _chonse = ½ m (v _t ² – vo ₂ ⁾ = ½ (0,5)(0 ² – 10 ² )

_{Chiwerengero chonse cha} W = (0,25)(-100) = -25 Joules

Chizindikiro chotsutsa chimasonyeza kuti komwe mpira ukusunthira ndi kosiyana ndi komwe mpira ukulowera. Kupita kwa mpira ukukwera mmwamba, pomwe komwe mpira ukulowera ndi kotsika. Mphamvu yokoka imagwira ntchito yoipa pa mpira, zomwe zikutanthauza kuti ntchito yochitidwa ndi mphamvu yokoka imawonjezera mphamvu yokoka ya mpira ndikuchepetsa mphamvu yake ya kinetic. Mphamvu yokoka imagwira ntchito yabwino ngati komwe mpira ukulowera ndi komwe mpira ukulowera (mpira ukusunthira pansi).

Yankho lolondola ndi C.

7. Mpira wolemera makilogalamu 1 umagwetsedwa popanda liwiro loyambirira kuchokera pamwamba pa nyumba kudzera pawindo A pamwamba mpaka pawindo B pansi ndi kusiyana kwa kutalika kwa 2,5 m (g = 10 ms ^-2 ). Kodi ntchito yochuluka bwanji yachitika kuti mpirawo usamutsidwe kuchokera pawindo A kupita pawindo B?

A. 5 Joule

B. 15 Joule

C. 20 Joule

D. 25 Joule

E. 50 Joule

Zokambirana

Amadziwika kuti :

Kulemera kwa mpira (m) = 1 kg

Liwiro loyambirira (v _o ) = 0 m/s

Kutalika (h) = mamita 2,5

Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ²

Funso : Khama lonse panthawi yoyenda kwa mpira

Yankho :

Liwiro lomaliza la mpira (v _t )

Mpira umagwa popanda liwiro loyambirira, motero kuyenda kwa mpirawo ndi kugwa kwaulere. Choyamba, werengani liwiro lomaliza la mpirawo pogwiritsa ntchito njira ya kugwa kwaulere. Popeza kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ² , kusintha kwa kutalika kwa mpirawo (h) = 2,5 metres, ndipo liwiro lomaliza (v _t ) limafunsidwa, chifukwa chake gwiritsani ntchito njira ya v _t ² = 2 gh

v _t ² = 2 gh = 2(10)(2,5) = 2(25)

v _t = √2(25) = 5√2

Kotero liwiro lomaliza la mpira ndi 5√2 m/s

Ntchito yonse = kusintha kwa mphamvu ya kinetic

Chiwerengero _chonse = ΔEK = ½ m (v _t ² – vo ₂ ⁾ = ½ (1){(5√2) ² – 0 ² }

Chiwerengero _chonse = ½ (25)(2) = 25 Joules

Yankho lolondola ndi D.

8. Chinthu cholemera makilogalamu awiri poyamba chimayenda pa liwiro la 72 km/h ^-1 . Pambuyo poyenda mamita 400, liwiro la chinthucho limakhala 144 km/h ^-1 ndipo (g = 10 m/s ^-2 ). Ntchito yonse yomwe chinthucho chinachita panthawiyo ndi...

A. 20 J

B. 60 J

C. 1.200 J

D. 2.000 J

E. 2.400 J

Zokambirana

Amadziwika kuti :

Kulemera kwa chinthu (m) = 2 kg

Liwiro loyambirira (v _o ) = 72 km/h = 20 m/s

Liwiro lomaliza (v _t ) = 144 km/h = 40 m/s

Mtunda woyenda = mamita 400

Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s ²

Anafunsa : Khama lonse

Yankho :

Ntchito yonse = kusintha kwa mphamvu ya kinetic

Chiwerengero _chonse = ΔEK = ½ m (v _t ² – vo ₂ ⁾ = ½ (2)(40 ² – 20 ² }

Chiwerengero _chonse = ½ (2)(1600 - 400) = 1200 Joules

Yankho lolondola ndi C.

9. Chinthu cholemera makilogalamu awiri chimayenda pamalo osalala pa liwiro la 2 m/s ^-1 . Ngati ntchito ya ma joules 21 yachitika pa chinthucho, liwiro la chinthucho lidzasintha kukhala…

A. 1 ms ^–1

B. 2 ms ^–1

C. 3 ms ^–1

D. 5 ms ^–1

E. 17 ms ^–1

Zokambirana

Amadziwika kuti:

Kulemera (m) = 2 kg

Liwiro loyambirira (v _o ) = 2 m/s

Ntchito (W) = 21 Joules

Funso: Liwiro lomaliza (v _t )

Yankho:

Chiphunzitso cha mphamvu ya work-kinetic chimanena kuti ntchito yonse yochitidwa pa chinthu ndi yofanana ndi kusintha kwa mphamvu ya kinetic ya chinthucho.

Chiwerengero chonse = ΔEK

Chiwerengero chonse = 1/2 mv _t ² -1/2 mv _o ²

Chiwerengero chonse = 1/2 m (v _t ² – _vo ² )

21 = 1/2 (2) (v _t ² – 2 ² )

21 = (v _t ² – 2 ² )

21 = v _t ² – 4

v _t ² = 21 + 4 = 25

v _t = √25

v _t = 5 m/s

Yankho lolondola ndi D.

10. Mpira wolemera magalamu 500 umaponyedwa molunjika mmwamba kuchokera pansi ndi liwiro loyambirira la 10 ms ^-2 . Ngati g = 10 ms ^-2 , ndiye kuti ntchito yokoka ya mpira ikafika kutalika kwake kwakukulu ndi...

A. 2,5 J
B. 5,0 J
C. 25 J
D. 50 J
E. 500 J

Zokambirana
Musanyalanyaze kukana kwa mpweya.
Ndizodziwika kuti :
Kulemera kwa mpira (m) = magalamu 500 = 0,5 kg
Liwiro loyambirira (v)_o) = 10 m/s²
Liwiro lomaliza (v)_t) = 0. Pa kutalika kwakukulu, chinthucho chimakhalabe kwakanthawi chisanabwerere m'mbuyo.
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s²
Anafunsa Ntchito (W) yochitidwa ndi mphamvu yokoka ya mpira
Yankhani :

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito :
Chiphunzitso cha mphamvu ya work-kinetic chimanena kuti ntchito yonse kapena usa Fomula ya chiphunzitso cha mphamvu ya ntchito-kinetic ya mphamvu yochokera pa chinthu ndi yofanana ndi kusintha kwa mphamvu ya kinetic ya chinthucho.
W_okwana = ΔEK = EK_t – EK_o
W_okwana = ½ mv_t² – ½ mv_o² = ½ m (v)_t² -v_o²)
Zambiri:
EK_t = mphamvu yomaliza ya kinetic, EK_o = mphamvu yoyambira ya kinetic, m = kulemera kwa chinthu, v_t = liwiro mapeto a chinthu, v_o = liwiro loyamba la chinthucho.
Khama lonse :
Ntchito yochitidwa ndi kulemera kwa mpira kuyambira nthawi yomwe mpira waponyedwa mpaka mpirawo utafika kutalika kwake kwakukulu ndi:
W_okwana = ½ m (v)_t² -v_o²) = ½ (0,5)(0² - 10²)
W_okwana = (0,25)(-100) = -25 Ma Joule
Chizindikiro chotsutsa chimasonyeza kuti komwe mpira ukusunthira ndi kosiyana ndi komwe mpira ukulowera. Kumene mpira ukusunthira ndi mmwamba, pomwe komwe mpira ukulowera ndi pansi. Mphamvu yokoka Kuchita ntchito yoipa pa mpira kumatanthauza kuti ntchito yochitidwa ndi mphamvu yokoka imapangitsa mphamvu yokoka ya mpirawo kukwera ndipo mphamvu ya kinetic ya mpirawo kutsika. Mphamvu yokoka imagwira ntchito yabwino ngati njira yokoka ya mpirawo ili yofanana ndi njira yomwe mpirawo umasunthira (mpirawo umapita pansi).
Yankho lolondola ndi C.

11. Mpira wolemera makilogalamu 1 umagwetsedwa popanda liwiro loyambirira kuchokera pamwamba pa nyumba kudzera pawindo A pamwamba mpaka pawindo B pansi ndi kusiyana kwa kutalika kwa 2,5 m (g = 10 ms ^-2 ). Kodi ntchito yochuluka bwanji yachitika kuti mpirawo usamutsidwe kuchokera pawindo A kupita pawindo B?

A. 5 Joule
B. 15 Joule
C. 20 Joule
D. 25 Joule
E. 50 Joule

Zokambirana
Ndizodziwika kuti :
Kulemera kwa mpira (m) = 1 kg
Liwiro loyambirira (v)_o) = 0 m/s
Kutalika (h) = mamita 2,5
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s²
Anafunsa : Ntchito yonse panthawi yoyenda kwa mpira
Yankhani :
Liwiro lomaliza la mpira (v)_t)
Mpira umagwa popanda liwiro loyambirira, kotero kuyenda kwa mpira kumaonedwa ngati kugwa kwaulere. Choyamba, werengani liwiro lomaliza la mpira pogwiritsa ntchito njira iyi. kuyenda kwaulere kwa kugwaAmadziwika kuti kuthamanga kwa mphamvu yokoka (g) = 10 m/s², kusintha kwa kutalika kwa mpira (h) = mamita 2,5 ndipo liwiro lomaliza (v) lafunsidwa_t) choncho gwiritsani ntchito njira v_t² = 2 gh
v_t² = 2 gh = 2(10)(2,5) = 2(25)
v_t = √2(25) = 5√2
Kotero liwiro lomaliza la mpira ndi 5√2 m/s
Ntchito yonse = kusintha kwa mphamvu ya kinetic
W_okwana = ΔEK = ½ m (v_t² -v_o²) = ½ (1){(5√2)² - 0²}
W_okwana = ½ (25)(2) = 25 Joule
Yankho lolondola ndi D.

12. Chinthu cholemera makilogalamu awiri poyamba chimayenda pa liwiro la makilomita 72 pa ola limodzi.^-1Pambuyo poyenda mamita 400, liwiro la chinthucho limafika 144 km/h.^-1 ndi (g = 10 ms^-2). Ntchito yonse yomwe chinthucho chinachita panthawiyo ndi…
A. 20 J
B. 60 J
C. 1.200 J
D. 2.000 J
E. 2.400 J
Zokambirana
Ndizodziwika kuti :
Kulemera kwa chinthu (m) = 2 kg
Liwiro loyambirira (v)_o) = 72 km/h = 20 m/s
Liwiro lomaliza (v)_t) = 144 km/h = 40 m/s
Mtunda woyenda = mamita 400
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s²
Anafunsa : Khama lonse
Yankhani :
Ntchito yonse = kusintha kwa mphamvu ya kinetic
W_okwana = ΔEK = ½ m (v_t² -v_o²) = ½ (2)(40² - 20²}
W_okwana = ½ (2)(1600 - 400) = 1200 Joules
Yankho lolondola ndi C.

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito

13. Galimoto yolemera tani imodzi imayamba kuchokera pamalo opumulira. Patapita kanthawi pang'ono liwiro lake ndi 5 m/s ^-1 . Kuchuluka kwa ntchito yomwe injini ya galimotoyo imachita ndi...

A. 1000 Joule
B. 2.500 Joule
C. 5.000 Joule
D. 12.500 Joule
E. 25.000 Joule

Zokambirana

Ndizodziwika kuti :
Kulemera (m) = tani imodzi = 1000 kg
Liwiro loyambirira (v)_o) = 0 (galimoto imayenda kuchokera pamalo osasuntha)
Liwiro lomaliza (v)_t) = 5 m/s
Anafunsa Kodi ntchito (W) yochitidwa ndi injini ya galimoto ndi yotani?
Yankhani :

Chiphunzitso cha mphamvu ya kinetic yogwira ntchito:
W_okwana = ½ m (v)_t² -v_o²)
Ntchito zomwe injini ya galimoto imachita ndi izi:
W_okwana = ½ (1000)(5² - 0²) = (500)(25 – 0) = (500)(25) = 12.500 Joules
Yankho lolondola ndi D.

Chiphunzitso cha Ntchito ndi Mphamvu za Makina

14. Yang'anani chithunzi cha kuyenda kwa zinthu zomwe zili pansipa!

Kulemera kwa chinthucho = 1 kg. Ngati coefficient of kinetic friction pakati pa block ndi pansi ndi 0,2, ndiye kuti mtengo wa displacement (s) ya chinthucho ndi… g = 10 m/s^2\

A. 10 m
B. 15 m
C. 20 m
D. 25 m
E. 30 m
Kukambirana:
Ndizodziwika kuti :
m = 1 kg, g = 10 m/s²mu_o = 10 m/s, v_t = 0
Anafunsa :
Kodi kusamuka kwa chinthu (zinthu) n'chiyani?
Yankhani :
Ntchito - chiphunzitso cha mphamvu yamakina :
Ntchito yochitidwa ndi mphamvu yosasintha = kusintha kwa mphamvu ya makina ya chinthu.
W_NC = EM₂ – EM₁
W_NC = (EP + EK)₂ – (EP + EK)₁ —- Chiyerekezo 1
Mphamvu yosasinthika yomwe imagwira ntchito pa chinthu ndi mphamvu ya kinetic friction:
W_NC = f_k s —- Equation 2
Kachitidwe ka kukangana ka kinetic :

Sinthani f_k mu equation 2 ndi f_k mu equation 3:
W_NC = f_k s = 2 s
Pamene chinthu chikuyenda, chimakumana ndi kusintha kwa mphamvu ya kinetic (mphamvu ya kinetic imachepa) pomwe mphamvu yokoka ya chinthucho siisintha (kusintha kwa mphamvu yokoka ndi zero).
W_NC = (EK)₂ – (EK)₁ = ½ mv_t² – ½ mv_o² = ½ m (v)_t² -v_o²)
2 s = ½(1)(0² - 10²)
2 s = (0,5)(100)
Masekondi 2 = 50
s = 50 / 2 = mamita 25
Yankho lolondola ndi D.

Lamulo losunga mphamvu zamakanika

15. Wosewera pa ayezi akutsetsereka kuchokera kutalika kwa A monga momwe zasonyezedwera pachithunzichi:
Ngati liwiro loyamba la skier = zero ndipo liwiro chifukwa cha mphamvu yokoka ndi 10 ms^-2, ndiye kuti liwiro la wosewerayo pa msinkhu B ndi...

A. √2 ms^-1
B. 5√2 ms^-1
C. 10√2 ms^-1
D. 20√2 ms^-1
E. 25√2 ms^-1

Zokambirana
Ndizodziwika kuti :
Liwiro loyambirira (v)_o= = 0
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s²
Kusintha kwa kutalika = mamita 50 - mamita 10 = mamita 40
Anafunsa : liwiro la wosewerayo pa msinkhu B?
Yankhani :
Lamulo losunga mphamvu zamakanika Amanena kuti mphamvu yoyambirira yamakina = mphamvu yomaliza yamakina.
Akayamba kusuntha kuchokera pa mfundo A, liwiro loyamba la wokwera ski = v_o = 0 kotero kuti mphamvu yoyambirira ya kinetic = EK_o = ½ mv_o² = 0. Mosiyana ndi zimenezi, pamene munthu wokwera ski ali ndi mphamvu yokoka poyamba = EP_o = mgh, pomwe h = mamita 50. Chifukwa chake mphamvu yoyambirira yamakina (EM)_o) = mphamvu yoyambira yokoka (EP)_o). Pakayenda kuchokera ku A kupita ku B, kutalika kwa wokwera phiri kumachepa, kotero mphamvu yokoka imachepa. Mphamvu yokoka simatayika koma imasinthidwa kukhala mphamvu yokoka. Kuwonjezeka kwa mphamvu yokoka kumawonetsedwa ndi kuwonjezeka kwa liwiro la wokwera phiri. Ngati wokwera phiri akafika pansi pa kutsika, mphamvu yonse yokoka imasinthidwa kukhala mphamvu yokoka. Pansi pa kutsika, mphamvu yokoka ndi zero, pomwe mphamvu yokoka imakhala pamlingo wake wapamwamba. Chifukwa chake mphamvu yomaliza yamakina (EM) ndi_t) = mphamvu yomaliza ya kinetic (EK)_t).

Nanga bwanji za mphamvu yokoka ndi mphamvu ya kinetic pa mfundo B? Pa mfundo B, mphamvu zina zokoka zimachepetsedwa ndikusinthidwa kukhala mphamvu ya kinetic. Makamaka, mphamvu ya kinetic pa mfundo B = kuchepa kwa mphamvu yokoka ngati chinthucho chikuganiziridwa kuti chikugwa momasuka kuchokera kutalika kwa mamita 40. Bwanji osagwiritsa ntchito kutalika kwa njira yopendekera koma kutalika kwa mamita 40? Ngati simukumvetsa izi, muyenera kuphunzira nkhani zokhudzana ndi mphamvu zosungira ndi ubale wawo ndi mphamvu zomwe zingatheke komanso lamulo losunga mphamvu zamakanika.

Liwiro la skier pamtunda B:
Mphamvu yomaliza yamakina = mphamvu yoyambirira yamakina
Mphamvu ya kinetic pamalo B = mphamvu yokoka pamtunda wa mamita 40
EK = EP
½ mv_t² = mgh
½ v_t² = gh
½ v_t² = (10)(50-10)
½ v_t² = (10)(40)
½ v_t² = 400
v_t² = (2)(400) = 800
v_t = √800 = √(2)(400) = 20√2 m/s
Yankho lolondola ndi D.

16. Chinthu chimayenda kuchokera pa mfundo A popanda liwiro loyambirira. Ngati palibe kukangana panthawi yoyenda, liwiro la chinthucho pamalo otsika kwambiri ndi...
A. 8 ms^-1
B. 12 ms^-1
C. 20 ms^-1
D. 24 ms^-1
E. 30 ms^-1
Zokambirana
Ndizodziwika kuti :
Unyinji wa chinthu = m
Liwiro loyambirira (v)_o= = 0
Kutalika (h) = mamita 20
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s²
Anafunsa : liwiro lomaliza (v_t)?
Yankhani :
Mphamvu yoyambirira yamakina (EM)₁) = mphamvu yokoka pa A (EP)_A) = mgh = (m)(10)(20) = 200 m
Mphamvu yomaliza yamakina (EM)₂) = mphamvu ya kinetic (EK) = ½ mv_t²
Liwiro la chinthucho pamalo otsika kwambiri kapena liwiro lomaliza la chinthucho v_t)?
Lamulo losunga mphamvu zamakanika:
EM₁ = EM₂
200 m = ½ mv_t²
200 = ½ v_t²
400 = v_t²
v_t= 20 m/s
Yankho lolondola ndi C.

 

Gwero la funso:

Mafunso a National Examination Physics a Senior High School/Vocational High School