Salon masu ra'ayin mazan jiya ba sunan wani ƙarfi ba, kamar nauyi, ƙarfin gogayya da sauransu. Ƙarfin masu ra'ayin mazan jiya yana bayyana yanayin ƙarfi. Idan jimlar aikin da ƙarfi ya yi a kan wani abu, a lokacin da abin ya motsa daga matsayinsa na asali har sai abin ya koma matsayinsa na asali, daidai yake da sifili, to ƙarfin ikon mai ra'ayin mazan jiya ne. Ana cewa ƙarfi mai ra'ayin mazan jiya ne idan aikin da ƙarfin ya yi a kan wani abu bai dogara da hanyar da abin ya bi ba sai dai kawai a kan canjin matsayinsa na farko da na ƙarshe.
Ma'anar salon ra'ayin mazan jiya ya fi sauƙin fahimta idan kun riga kun fahimta fahimtar aiki a fannin kimiyyar lissafiYi nazarin tambayoyi guda biyu masu zuwa don fahimtar manufar ƙarfin mazan jiya.
Misali na 1
Ka yi la'akari da wani abu yana motsawa a tsaye sama sannan abin ya motsa a tsaye zuwa matsayinsa na asali.
Idan abu ya motsa sama, alkiblar matsar da abu yana sama, yayin da alkiblar ƙarfin nauyi ko nauyi (w) yana ƙasa. Alkiblar matsar da abu yana akasin alkiblar ƙarfin nauyi, saboda haka ƙarfin nauyi yana aiki mara kyau.
W1 = Fs s = wh (cos 180) = wh (-1) = – wh = – mgh
Idan abu ya koma ƙasa zuwa ga matsayinsa na asali, alkiblar matsar da abu zuwa ƙasa take, alkiblar ƙarfin nauyi kuma tana ƙasa. Alkiblar matsar da abu zuwa ƙasa take daidai da alkiblar ƙarfin nauyi, don haka ƙarfin nauyi yana yin aiki mai kyau.
W2 = Fs s = wh (cos 0) = wh (1) = wh
Jimillar aikin da ƙarfin nauyi ya yi akan wani abu a lokacin da abin ya motsa sama sannan ya faɗi daidai yake da sifili.
WTotal = W1 +W2 = – wh + wh = 0
Misali, nauyin abu (m) = 1 kg, saurin nauyi (g) = 10 m/s2 kuma tsayi (h) = mita 1 sannan W1 = -10 Joules da W2 = Joules 10. Jimlar aiki = – Joules 10 + Joules 10 = 0
Misali na 2
Ka yi la'akari da wani abu da ke motsawa daga kwari zuwa kololuwa sannan ya koma kwarin.
Muddin abu yana motsawa akan jirgin sama mai karkata, sai dai ɓangaren kwance na ƙarfin nauyi (w sin theta) ne ke aiki akan abu. Lokacin da abu ya motsa daga kwarin zuwa saman jirgin sama mai karkata, alkiblar motsawa ta saba wa alkiblar ɓangaren kwance na ƙarfin nauyi (w sin theta) don haka ƙarfin nauyi yana aiki mara kyau.
Aikin da ƙarfin nauyi ke yi a kan wani abu yayin da yake motsawa daga kwarin zuwa kololuwar.
W1 = – Fs = – (w sin theta)(s) = – ws sin theta
Domin kuwa zunubin theta = h / s ko h = s zunubin theta to an canza dabarar da ke sama zuwa
W1 = – wh = – mgh
Idan abu ya motsa daga kololuwa zuwa kwari, tafiyar tana daidai da alkiblar da aka yi a kwance na ƙarfin nauyi, don haka ƙarfin nauyi yana yin aiki mai kyau.
W2 = w = mgh
Jimillar ƙoƙari
Jimilla = – mgh + mgh = 0
Misali, nauyin abu (m) = 1 kg, saurin nauyi (g) = 10 m/s2 kuma tsayi (h) = mita 1 sannan W1 = -10 Joules da W2 = Joules 10. Jimlar aiki = – Joules 10 + Joules 10 = 0
Bisa ga dabarar da aka yi amfani da ita a misali na 2, za a iya kammala da cewa aikin da ƙarfin nauyi ke yi a kan wani abu lokacin da abin ya motsa tare da jirgin sama mai karkata, nisan s iri ɗaya ne da aikin da ƙarfin nauyi ke yi a kan abu idan abin ya motsa a tsaye a nisan h.
Don haka aikin da ƙarfin nauyi ke yi ba ya dogara ne akan hanyar da aka yi tafiya ba, sai dai kawai akan canjin tsayi. A wata ma'anar, aikin da ƙarfin nauyi ke yi ƙarfin nauyi kawai ya dogara ne akan matsayin farko da matsayin ƙarshe.
Waɗannan misalai guda biyu sun nuna cewa ƙarfin nauyi ƙarfin ra'ayi ne na masu ra'ayin mazan jiya. Ƙarfi ƙarfin ra'ayi ne idan ya cika sharuɗɗa biyu. Na farko, jimlar aikin da ƙarfin ya yi akan wani abu a lokacin da abin ya motsa daga matsayinsa na farko har sai ya koma matsayinsa na farko daidai yake da sifili (kwatanta misali na 1). Na biyu, jimlar aikin da ƙarfin ya yi akan wani abu ba ya dogara ne akan hanyar da abin ya bi ba amma ya dogara ne akan canjin matsayi (kwatanta misali na 2).
Wasu ƙarfin da ke cikin ƙarfin masu ra'ayin mazan jiya sune ƙarfin nauyi, ƙarfin lantarki, da ƙarfin maganadisu.
Misali na 3
Ƙarfin Coulomb da ƙarfin nauyi ƙarfi ne masu ra'ayin mazan jiya.
Domin kuwa
Ƙarfin Coulomb da ƙarfin nauyi suna da daidaiton da ya yi daidai da murabba'in nisa.
Tattaunawa
Ƙarfin wutar lantarki da ƙarfin nauyi ƙarfi ne na masu ra'ayin mazan jiya, ba wai saboda girmansu ya yi daidai da murabba'in nisan ba. Dukansu ƙarfi ne na masu ra'ayin mazan jiya domin aikin da aka yi don ɗaukar kaya a ƙarƙashin tasirin waɗannan ƙarfi biyu bai dogara da hanyar ko hanyar da aka yi tafiya ba, sai dai kawai a kan matsayin farko da na ƙarshe na nauyin.
Ƙarfi ƙarfi ne mai ra'ayin mazan jiya idan yana aiki akan wani abu…
(1) ya dogara ne kawai akan yanayin farko da yanayin ƙarshe
(2) iri ɗaya ne da canjin kuzarin da ke cikin abu
(3) bai dogara da siffar hanyar motsi ba
(4) ba ya dogara da canje-canje a cikin makamashi mai yuwuwa ba
Tattaunawa
Ƙarfi ƙarfi ne mai ra'ayin mazan jiya idan yana aiki akan abu
(1) ya dogara ne kawai akan yanayin farko da yanayin ƙarshe
(3) bai dogara da siffar hanyar motsi ba
