Zitsanzo 5 za mafunso okhudza kuyenda
1. Kulemera kwa katundu mumlengalenga ndi 3 N, kulemera kwa katundu m'madzi ndi 2,8 N. Kodi madziwo amagwiritsa ntchito mphamvu yochuluka bwanji pa katunduyo?
Kukambirana:
2. Chitsulo chimalemera 100 N chikayesedwa mumlengalenga ndi 80 N chikayesedwa m'madzi. Kodi kuchuluka kwa chitsulocho ndi kotani?
Kukambirana:
Amadziwika kuti:
w = 100 N
mpweya wozungulira = 80 N
Anafunsa kuti: Voliyumu yachitsulo ?
Kuchuluka kwa chitsulo choviikidwa m'madzi ndi kofanana ndi kuchuluka kwa madzi omwe achotsedwa.
3. Mwala umakhala ndi kulemera kwa makilogalamu 10. Ukauyeza m'madzi, kulemera kwa mwala ndi makilogalamu 8,2. Kodi kulemera kwa mwala ndi kotani?
Kukambirana:
Amadziwika kuti:
g = 9,8 m/s2
m = 10 makilogalamu
m madzi = 8,2 kg
Anafunsa: Kuchuluka kwa thanthwe ( ?
Yankho:
4. Chipika chamatabwa chokhala ndi kutalika kwa 2,5 m, m'lifupi mwake 0,5 m ndi makulidwe a 0,4 m. Ngati matabwa amira m'madzi, ndipo kuchuluka kwa madzi ndi 1000 kg/m3 , ndiye kuti kukula kwa kuthamanga kwa madzi mmwamba ndi … (g = 10 N/kg)
A. 400 N
B. 500 N
C. 4.000 N
D. 5.000 N
Zokambirana
Amadziwika kuti:
Voliyumu ya cuboid (V) = kutalika x m'lifupi x makulidwe = 2,5 x 0,5 x 0,4 = 0,5 m 3
Kuchuluka kwa madzi ( ρ ) = 1000 kg/ m3
Kuthamanga chifukwa cha mphamvu yokoka (g) = 10 N/kg
Anafunsa: Kukula kwa mphamvu yothamanga
Yankho:
Fomula ya mphamvu yolimba:
F = ρ g V
Kufotokozera: F = mphamvu yoyandama, ρ = Kuchulukana, g = kuthamanga kwa mphamvu yokoka, V = voliyumu
Ma voliyumu onse a zinthu zomwe zili pansi pa madzi kotero mphamvu yoyandama imawerengedwa pogwiritsa ntchito njira yomwe ili pamwambapa.
F = (1000)(10)(0,5) = (1000)(5) = 5000 Newtons
Yankho lolondola ndi D.
5. Kulemera kwa chinthu chomwe chili mumlengalenga ndi 100 N, kenako chimayikidwa mumadzimadzi kotero kuti voliyumu imawonjezeka ndi 1,5 m3 . Ngati mphamvu yeniyeni ya madzi ndi 10 N/m3 , ndiye kuti kulemera kwa chinthu chomwe chili mumadzimadzi ndi...
A. 1.500 N
B. 115 N
C. 85 N
D. 6,7 N
Zokambirana
Amadziwika kuti:
Kulemera kwa chinthu mumlengalenga (w) = 100 Newtons
Kuwonjezeka kwa voliyumu ya madzi = voliyumu ya chinthu chomizidwa m'madzi (V) = 1,5 m 3
Mphamvu yeniyeni ya madzi = 10 N/m 3
Kufunidwa: Kulemera kwa chinthu mu madzi
Yankho:
Fomula yowerengera kulemera kwa chinthu mu madzi:
Kulemera kwa chinthu mumadzi = kulemera kwa chinthu mumlengalenga - kukula kwa mphamvu yoyandama
Kulemera kwa chinthu mu madzi = 100 Newtons – kukula kwa mphamvu yoyandama
Choyamba werengani kukula kwa mphamvu yoyandama kuti muthe kuwerengera kulemera kwa chinthu chomwe chili mumadzi.
Fomula ya mphamvu yolimba:
F A = ρ g V
Zambiri:
F A = mphamvu yolimba = mphamvu yogwiritsidwa ntchito ndi madzi pa chinthu chomwe chili mumadzi
ρ = kuchuluka kwa madzi
g = kuthamanga chifukwa cha mphamvu yokoka
V = kuchuluka kwa chinthu chomizidwa m'madzi
Kuthamanga kwa mphamvu yokoka (g) kumadziwika, kuchuluka kwa chinthu chomwe chamira m'madzimadzi kumadziwika, koma kuchuluka kwake sikudziwikabe. Chifukwa chake, choyamba werengani kuchuluka kwa madzimadzi.
Mphamvu yokoka yeniyeni:
Mphamvu yeniyeni ya madzi = 10 N/m 3
w / V = 10 N/m 3
mg / V = 10 N/m 3
m (10) / V = 10 N/m 3
m / V = 1 kg/m 3
ρ = 1 kg/ m3
Kotero kuchuluka kwa madzi ndi 1 kg/ m3
Mphamvu ya mphamvu ya kulimba mtima :
F A = ρ g V = ( 1 kg/m 3 )(10 m/s 2 )(1,5 m 3 ) = 15 kg m/s 2 = 15 Newtons
Kulemera kwa chinthu mu madzi:
Kulemera kwa chinthu mu madzi = 100 Newtons – 15 Newtons
Kulemera kwa chinthu mu madzi = 85 Newtons
Yankho lolondola ndi C.
Zitsanzo za mafunso okhudza lamulo la Archimedes
