Zitsanzo 8 za Mafunso Okhudza Kuthamanga kwa Mzere
1. Chinthu cholemera makilogalamu 1 chimayenda pa liwiro la 10 m/s. patsogolo chinthucho ndi…
Zokambirana
Ndizodziwika kuti :
Kulemera (m) = 1 kg
Liwiro (v) = 10 m/s
Anafunsa : mzere wolunjika (p)
Yankhani :
Fomula ya mphamvu: p = mv
Kufotokozera: p = mphamvu, m = kulemera, v = liwiro.
Mphamvu ya chinthu ndi:
p = mv = (1)(10) = 10 kg m/s2
2. Zinthu ziwiri, chilichonse chokhala ndi kulemera kwa 2 kg ndi 4 kg, zikuyenda pa liwiro la 20 m/s. Mphamvu ya chinthu chilichonse ndi…
Zokambirana
Ndizodziwika kuti :
Unyinji wa chinthu A (mA) = 2 kg
Kulemera kwa chinthu B (mB) = 4 kg
Liwiro la chinthu A (v)A) = 20 m/s
Liwiro la chinthu B (v)B) = 20 m/s
Anafunsa : mphamvu ya chinthu A (p)A) ndi mphamvu ya chinthu B (pB)
Yankhani :
Mphamvu ya chinthu A :
pA = mA vA = (2)(20) = 40 kg m/s
Mphamvu ya chinthu B :
pB = mB vB = (4)(20) = 80 kg m/s
Ngati liwiro la zinthu zonse ziwiri ndi lofanana, chinthu chokhala ndi kulemera kwakukulu chimakhala ndi mphamvu yayikulu.
3. Zinthu A ndi B chilichonse chili ndi kulemera kwa 2 kg. Chinthu A chimayenda pa liwiro la 2 m/s ndipo chinthu B chimayenda pa liwiro la 4 m/s. Mphamvu ya chinthu A ndi chinthu B ndi…
Zokambirana
Ndizodziwika kuti :
Unyinji wa chinthu A (mA) = 2 kg
Kulemera kwa chinthu B (mB) = 2 kg
Liwiro la chinthu A (v)A) = 2 m/s
Liwiro la chinthu B (v)B) = 4 m/s
Anafunsa : mphamvu ya chinthu A (p)A) ndi mphamvu ya chinthu B (pB)
Yankhani :
Mphamvu ya chinthu A :
pA = mA vA = (2)(2) = 4 kg m/s
Mphamvu ya chinthu B :
pB = mB vB = (2)(4) = 8 kg m/s
Ngati unyinji wa zinthu zonse ziwiri ndi wofanana, chinthu chomwe chili ndi liwiro lalikulu chimakhala ndi mphamvu yayikulu.
4. Chinthu cholemera makilogalamu 5 chimakhala chili pamalo opumulira. Mphamvu ya chinthucho ndi…
Zokambirana
Ndizodziwika kuti :
Kulemera kwa chinthu (m) = 5 kg
Liwiro la chinthu (v) = 0
Anafunsa : mphamvu ya chinthu (p)
Yankhani :
p = mv = (5)(0) = 0
Ngati chinthu chili pamalo opumulira, ndiye kuti ngakhale kulemera kwa chinthucho kukhale kwakukulu bwanji, mphamvu ya chinthucho ndi zero.
5. Mu masewera a baseball, mpira wolemera makilogalamu 0,5 umayamba kuyenda pa liwiro la 2 ms -1 . Kenako mpirawo umamenyedwa ndi mphamvu F motsutsana ndi kayendedwe ka mpirawo, kotero kuti liwiro la mpirawo limasintha kufika pa 6 ms -1 . Ngati mpirawo wakhudzana ndi bat kwa masekondi 0,01, ndiye kuti kusintha kwa mphamvu kumakhala...
A. 8 kg ms -1
B. 6 kg ms -1
C. 5 kg ms -1
D. 4 kg ms -1
E. 2 kg ms -1
Zokambirana
Amadziwika kuti:
Kulemera kwa mpira (m) = 0,5 kg
Liwiro loyambirira (v o ) = 2 m/s
Liwiro lomaliza (v t ) = -6 m/s
Nthawi yopuma (t) = masekondi 0,01
Anafunsa: Kusintha kwa mphamvu
Yankho:
Fomula yosinthira mphamvu:
∆ 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
Yankho lolondola ndi D.
6. Chinthu cholemera magalamu 100 chimayenda pa liwiro la 5 ms -1 . Kuti chiyimitse chinthucho, mphamvu yotsutsa F imagwira ntchito kwa masekondi 0,2. Kukula kwa mphamvu F ndi...
A. 0,5 N
B. 1,0 N
C. 2,5 N
D. 10 N
E. 25 N
Zokambirana
Amadziwika kuti:
Kulemera kwa chinthu (m) = magalamu 100 = 100/1000 = 0,1 kg
Liwiro loyambirira la chinthucho (v o ) = 5 m/s
Liwiro lomaliza la chinthucho (v t ) = 0
Nthawi ya kugundana (Δt) = masekondi 0,2
Funso: Kukula kwa mphamvu F
Yankho:
Chiphunzitso cha impulse-momentum chimanena kuti impulse ndi yofanana ndi kusintha kwa mphamvu.
Ine = ΔP
F (Δt) = m (v t – vo o )
F (0,2) = 0,1 (0 – 5)
F (0,2) = -0,5
F = -0,5 / 0,2
F = -2,5N
Kukula kwa mphamvu ndi ma Newton 2,5. Chizindikiro chotsutsa chimasonyeza komwe mphamvuyo ikupita. Chizindikiro chotsutsa cha Gaa chimasonyeza kuti mphamvuyo ikulunjika mosiyana ndi kayendedwe ka chinthucho.
Yankho lolondola ndi C.
7. Mpira wa tenisi wolemera magalamu 100 umagwetsedwa pansi kuchokera kutalika kwa 20 cm popanda liwiro loyambirira. Pambuyo pogunda pansi, mpira umadumphadumpha ndi liwiro la 1 ms -1 ndi (g = 10 ms -2 ). Kusintha kwa mphamvu ya mpira ndi...
A. 0,1 Ns
B. 0,3 Ns
C. 0,5 Ns
D. 0,8 Ns
E. 0,9 Ns
Zokambirana
Amadziwika kuti :
Kulemera kwa mpira (m) = magalamu 100 = 0,1 kg
Kutalika (h) = 20 cm = 0,2 mamita
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2
Liwiro la mpira nthawi yomweyo ukangogunda pansi (v t ) = 1 m/s
Anafunsa : kusintha kwa mphamvu ya mpira
Yankho :
Liwiro la mpira usanagwe (v)o)
Werengerani liwiro la mpira musanagunde pogwiritsa ntchito njira yoyendetsera mpira wa free fall. Popeza kutalika kwa mpira wa free fall (h) = 0,2 metres, kuthamanga chifukwa cha mphamvu yokoka (g) = 10 m/s 2 ndi liwiro la mpira ukagunda pansi zimafunsidwa, chifukwa chake njira yogwiritsira ntchito v 2 = 2 gh imagwiritsidwa ntchito.
v 2 = 2 (10)(0,2) = 4
v = √4 = -2 m/s
Chimapatsidwa chizindikiro chotsutsa chifukwa chakuti komwe mpira ukuyenda usanagunde pansi kumakhala kosiyana ndi komwe mpira ukuyenda utatha kugundana ndi pansi.
Kusintha kwa mphamvu ya mpira (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 Sekondi ya Newton
Yankho lolondola ndi B.
8. Chinthu chomwe poyamba chinali pamalo opumulira chinaphulika m'zigawo ziwiri ndi chiŵerengero cha 3:2. Gawo lomwe linali ndi kulemera kwakukulu linaponyedwa pa liwiro la 20 ms -1 . Kotero liwiro lomwe gawo laling'ono linaponyedwa ndi...
A. 13,3 ms –1
B. 20 ms –1
C. 30 ms –1
D. 40 ms –1
E. 60 ms –1
Zokambirana
Amadziwika kuti:
Kulemera kwa chinthu 1 musanagunde = m
Liwiro la chinthu 1 chisanachitike kugundana = 0 (chinthu chili pamalo opumulira)
Kulemera kwa gawo lachiwiri pambuyo pa kugundana (m1 ) = 1m
Kulemera kwa gawo lachiwiri pambuyo pa kugundana (m2 ) = 2m
Liwiro la gawo 1 pambuyo pa kugundana (v 1 ') = 20 m/s
Funso: Liwiro la gawo lachiwiri pambuyo pa kugundana (v 2 ')
Yankho:
Njira ya lamulo losunga mphamvu:
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 v 2 '
v 2 ' = -60/2
v 2 ' = -30 m/s
Chizindikiro chotsutsa chimasonyeza kuti njira yoyendera ya gawo lachiwiri ndi yosiyana ndi njira ya gawo loyamba. Mwachitsanzo, ngati gawo loyamba laponyedwa kum'mawa, ndiye kuti gawo lachiwiri laponyedwa kumadzulo.
Yankho lolondola ndi C.
Gwero la funso:
Mafunso a National Examination Physics a Senior High School/Vocational High School
