Lamulo la Coulomb

Mu nkhani yokhudza chaji yamagetsi dani mitundu ya magetsi Amafotokozedwa kuti monga momwe ma chaji amagetsi amakokerana pomwe mosiyana ndi ma chaji amagetsi amakokerana. Mwanjira ina, zinthu zomwe zili ndi mphamvu yabwino zimakokera zinthu zomwe zili ndi mphamvu zoyipa, zinthu zomwe zili ndi mphamvu zabwino zimakokera zinthu zomwe zili ndi mphamvu zabwino, ndipo zinthu zomwe zili ndi mphamvu zoyipa zimakokera zinthu zomwe zili ndi mphamvu zoyipa. Chochitikachi chikuwonetsa kukhalapo kwa mphamvu yamagetsi yomwe imagwira ntchito pazinthu zomwe zili ndi mphamvu zabwino komanso zinthu zomwe zili ndi mphamvu zoyipa. Ndi zinthu ziti zomwe zimakhudza kukula kwa mphamvu yamagetsi pakati pa zinthu zomwe zili ndi mphamvu zamagetsi?

Katswiri wa sayansi ya zakuthambo wa ku France Charles Coulomb (1736–1806) adachita zoyeserera zingapo m'zaka za m'ma 1780 kuti afufuze zinthu zomwe zimakhudza kukula kwa mphamvu yamagetsi pakati pa zinthu zamagetsi. Chipangizo chomwe Coulomb adagwiritsa ntchito chinali chofanana ndi chomwe Cavendish adagwiritsa ntchito pofufuza mphamvu yokoka, yotchedwa torsion balance. Coulomb adafufuza mphamvu yamagetsi, motero adagwiritsa ntchito mipira iwiri yachitsulo yoyendetsedwa ndi magetsi, pomwe Cavendish adafufuza mphamvu yokoka, chifukwa chake adagwiritsa ntchito mipira iwiri yolemera yopanda magetsi.

Momwe sikelo ya torque imagwirira ntchito  

 
Momwe sikelo ya torque imagwirira ntchito imagwirizana ndi nkhaniyo mphamvu kapena mphindi ya mphamvu mu chaputala mphamvu zozungulira.
Malo omwe ali mu torsion balance ndi vacuum kuti magetsi asamayendetsedwe mumlengalenga. Kudziwa kuchuluka kwa magetsi omwe ali pa mpira wolimba kumachitika pogwiritsa ntchito njira yotsatirayi. Poyamba, mpira wolimba A umapangidwa ndi magetsi kudzera mu conduction kapena friction. Mpira wolimba A womwe wayikidwa ndi magetsi umalumikizidwa ndi mpira wolimba B womwe suli wolowerera pogwiritsa ntchito conductor yamagetsi mpaka magetsi a mpira wolimba A agawidwe mofanana ndi mpira wolimba B. Ngati kuchuluka kwa magetsi a mpira wolimba A kuli ½ ndiye kuti kuchuluka kwa magetsi a mpira wolimba B kuli ½. Kenako, mpira wolimba B ndi mpira wolimba C zimalumikizidwa ndi conductor yamagetsi mpaka magetsi a mpira wolimba B agawidwe mofanana ndi mpira wolimba C. Ngati kuchuluka kwa magetsi a mpira wolimba B kuli ¼ ndiye kuti kuchuluka kwa magetsi a mpira wolimba C kuli ¼. Kuchuluka kwa magetsi ndi mtundu wa magetsi a mpira wolimba 1 ndi mpira wolimba 2 zimapezeka motere.

Chigawo cholimba 1 ndi chigawo cholimba 2 zimayendetsedwa ndi magetsi kotero kuti zigawo ziwiri zolimba zimatsutsana ngati zigawo ziwirizo zili ndi mphamvu yofanana yamagetsi kapena zimakokerana ngati zigawo ziwirizo zili ndi mphamvu yosiyana yamagetsi. Kupezeka kwa mphamvu yokoka kapena yobweza pakati pa zigawo ziwiri zolimba zomwe zimayendetsedwa ndi magetsi kumapangitsa kuti chigawo cholimba 2 chizungulire. Ngodya ya ulendo wa chigawo cholimba 2 imayesedwa kuti adziwe mphamvu yamagetsi yomwe ikugwira ntchito pa zigawo ziwirizo zolimba.

Zinthu zomwe zimakhudza mphamvu yamagetsi

Kutengera ndi zoyeserera zomwe zidachitika pogwiritsa ntchito torsion balance, Coulomb adapeza zinthu zingapo.
– Mu kuyesera uku, mtunda pakati pa mipira iwiri yolimba nthawi zonse umakhala wofanana. Ngati kuchuluka kwa mphamvu yamagetsi pa mpira wolimba 1 kuli 1 ndipo kuchuluka kwa mphamvu yamagetsi pa mpira wolimba 2 kuli 1 ndiye kuti mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba ndi 1. Ngati kuchuluka kwa mphamvu yamagetsi pa mpira wolimba 1 kuli 2 ndipo kuchuluka kwa mphamvu yamagetsi pa mpira wolimba 2 kuli 2 ndiye kuti mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba ndi 4. Coulomb adatsimikiza kuti kukula kwa mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba kumagwirizana ndi kuchuluka kwa mphamvu pa mipira yonse yolimba (F ≈ q₁ q₂).
– Mu kuyesera uku, kuchuluka kwa mphamvu pa mipira yonse yolimba nthawi zonse kumakhala kofanana. Ngati mtunda pakati pa mipira iwiri yolimba ndi 1 ndiye kuti mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba ndi 1. Ngati mtunda pakati pa mipira iwiri yolimba ndi 2 ndiye kuti mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba ndi ¼. Coulomb adatsimikiza kuti kukula kwa mphamvu yamagetsi yomwe imagwira ntchito pa mipira yonse yolimba ndi kofanana ndi sikweya ya mtunda (F ≈ 1 / r).²)

Lamulo la Coulomb

Lamulo la Coulomb ndi lamulo la fizikisi lomwe limafotokoza ubale womwe ulipo pakati pa mphamvu yamagetsi, mphamvu yamagetsi, ndi mtunda pakati pa mphamvu. Lamuloli linapangidwa kutengera zoyeserera za Coulomb, monga tafotokozera m'nkhani yapitayi.

Lamulo la Coulomb akunena kuti kukula kwa mphamvu yomwe tinthu tamagetsi timagwiritsa ntchito pa tinthu tina tamagetsi timagwiritsa ntchito molingana ndi zomwe zapezeka pa kuchuluka kwa mphamvu za tinthu tamagetsi tiwiri ndipo motsutsana ndi sikweya ya mtunda pakati pa tinthu tamagetsi tiwiri timene timagwiritsa ntchito. Mphamvu imeneyi imagwira ntchito molunjika polumikiza tinthu tamagetsi tiwiri. Mphamvu yamagetsi imanyansa ngati mphamvu yamagetsi ya tinthu tamagetsi tiwiri ndi yofanana ndipo mphamvu yamagetsi imakopa ngati mphamvu yamagetsi ya tinthu tamagetsi tiwiri si yofanana.

Lamulo la Coulomb likhoza kufotokozedwa mu equation ya masamu:
Kufotokozera kwa fomula:
F₁₂ = mphamvu yamagetsi pakati pa tinthu 1 ndi tinthu 2
q₁ = chiwerengero cha zolipiritsa za tinthu 1
q₂ = chiwerengero cha magetsi a tinthu 2
r₁₂ = mtunda pakati pa tinthu 1 ndi tinthu 2
(werengani: epsilon zero) = 8,854 x 10^-12 C²/Nm²
k = (chosasintha cha Coulomb) = 9 x 10⁹ Nm²/C²
F₂₁ ndi mphamvu yogwiritsidwa ntchito ndi mlandu q₂ pa mtengo q₁, pomwe F₁₂ ndi mphamvu yogwiritsidwa ntchito ndi mlandu q₁ pa mtengo q₂. F₂₁ ndi F₁₂ kubwezerana wina ndi mnzake pamene mlandu uli q₁ ndi q₂ zofanana ndipo zimakopana wina ndi mnzake pamene mphamvu ndi q₁ ndi q₂ osati mtundu womwewo.
F₂₁ ndi F₁₂ ali ndi phindu lofanana, mbali yosiyana ndipo amachita zinthu zosiyanasiyana, motero mphamvu ziwirizi ndi gulu la mphamvu yochitapo kanthu.