Izibonelo ezi-5 zemibuzo yokuphaphazela
1. Isisindo somthwalo osemoyeni singama-N angu-3, isisindo somthwalo osemanzini singama-N angu-2,8. Angakanani amandla amanzi asebenzisa umthwalo?
Ingxoxo:
2. Insimbi inesisindo esingu-100 N uma ilinganiswa emoyeni kanye no-80 N uma ilinganiswa emanzini. Ungakanani umthamo wensimbi?
Ingxoxo:
Kuyaziwa ukuthi:
w = 100 N
umoya opholile = 80 N
Kubuziwe: Ivolumu yensimbi ?
Umthamo wensimbi ecwiliswe emanzini ulingana nomthamo wamanzi asusiwe.
3. Idwala linesisindo esingamakhilogremu ayi-10. Uma lilinganiswa emanzini, isisindo salo singu-8,2 kg. Kungakanani ubuningi bedwala?
Ingxoxo:
Kuyaziwa ukuthi:
g = 9,8 m/s2
m = 10 kg
amanzi = 8,2 kg
Kubuziwe: Ubuningi bedwala (?
Impendulo:
4. Ibhloko lokhuni elinobude obungu-2,5 m, ububanzi obungu-0,5 m kanye nobukhulu obungu-0,4 m. Uma izinkuni zicwiliswe emanzini, futhi ubuningi bamanzi bungu-1000 kg/m3 , khona-ke ubukhulu bokucindezela okuphezulu bungu … (g = 10 N/kg)
A. 400 N
B. 500 N
C. 4.000 N
D. 5.000 N
Ingxoxo
Kuyaziwa ukuthi:
Umthamo we-cuboid (V) = ubude x ububanzi x ubukhulu = 2,5 x 0,5 x 0,4 = 0,5 m 3
Ubuningi bamanzi ( ρ ) = 1000 kg/ m3
Ukusheshisa ngenxa yamandla adonsela phansi (g) = 10 N/kg
Kubuziwe: Ubukhulu bamandla anamandla
Impendulo:
Ifomula yamandla okuqina:
F = ρ g V
Incazelo: F = amandla okuntanta, ρ = Ubuningi, g = ukusheshisa kwamandla adonsela phansi, V = ivolumu
Wonke amavolumu ezinto ezicwiliswe emanzini ukuze amandla okuntanta abalwe kusetshenziswa ifomula engenhla.
F = (1000)(10)(0,5) = (1000)(5) = 5000 amaNewton
Impendulo efanele ngu-D.
5. Isisindo sento esemoyeni singama-N ayi-100, bese ifakwa kuketshezi ukuze ivolumu ikhuphuke ngo-1,5 m3 . Uma amandla adonsela phansi athile oketshezi angama-N ayi-10/m3 , khona-ke isisindo sento eseketshezini...
A. 1.500 N
B. 115 N
C. 85 N
D. 6,7 N
Ingxoxo
Kuyaziwa ukuthi:
Isisindo sento emoyeni (w) = 100 Newtons
Ukwanda kwevolumu yoketshezi = ivolumu yento ecwiliswe oketshezini (V) = 1,5 m 3
Ubukhulu obuthile boketshezi = 10 N/m 3
Okufunwayo: Isisindo sento eketshezini
Impendulo:
Ifomula yesisindo sento eketshezini:
Isisindo sento esemanzini = isisindo sento esemoyeni – ubukhulu bamandla okuphapha
Isisindo sento eketshezini = 100 Newtons – ubukhulu bamandla okuphapha
Okokuqala bala ubukhulu bamandla okuntanta ukuze ukwazi ukubala isisindo sento ekuketshezi.
Ifomula yamandla okuqina:
F A = ρ g V
Imininingwane:
F A = amandla avuselelayo = amandla asetshenziswa uketshezi entweni eseketshezini
ρ = ukuminyana koketshezi
g = ukusheshisa ngenxa yamandla adonsela phansi
V = ivolumu yento ecwiliswe oketshezini
Ukusheshisa okubangelwa amandla adonsela phansi (g) kuyaziwa, umthamo wento ecwiliswe oketshezini uyaziwa, kodwa ubuningi abukaziwa. Ngakho-ke, qala ubale ubuningi boketshezi.
Amandla adonsela phansi athile:
Ubukhulu obuthile boketshezi = 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/m 3
Ngakho-ke ubuningi boketshezi buyi-1 kg/ m3
Ubukhulu bamandla okuqina :
F A = ρ g V = ( 1 kg/m 3 )(10 m/s 2 )(1,5 m 3 ) = 15 kg m/s 2 = 15 AmaNewton
Isisindo sento eseluketshezini:
Isisindo sento ewuketshezi = 100 Newtons – 15 Newtons
Isisindo sento ewuketshezi = 85 Newtons
Impendulo efanele ngu-C.
Imibuzo eyisibonelo ngomthetho ka-Archimedes
