Nā nīnau hoʻohālike e kūkākūkā ana i nā Postulates mua a me ka lua o Einstein
ʻO Albert Einstein, kekahi o nā mea koʻikoʻi loa i ka physics, ua hoʻolauna i ʻelua mau postulate koʻikoʻi i kāna kumumanaʻo kūikawā o ka relativity, i ʻike ʻia ʻo nā postulate mua a me ka lua o Einstein. Ua hoʻokūkū kēia mau postulate i nā ʻike kuʻuna o ka hakahaka a me ka manawa a ua hoʻomākaukau i ke ala no nā ʻike kipi i ka physics. Ma kēia ʻatikala, e ʻeli hohonu mākou i kēia mau postulate ʻelua a hāʻawi i kekahi mau laʻana e kōkua iā mākou e hoʻomaopopo i nā manaʻo pili.
ʻO ka Postulate mua a Einstein
ʻO ka postulate mua a Einstein, i ʻike ʻia hoʻi ʻo ke kumumanaʻo o ka relativity, ke ʻōlelo nei ua like nā kānāwai o ka physics ma nā kiʻina kuhikuhi inertial āpau. I nā huaʻōlelo ʻē aʻe, ʻaʻohe kiʻina kuhikuhi inertial i ʻoi aku ka maikaʻi ma mua o kekahi, a pono e kūlike nā nānā kino āpau mai kekahi kiʻina kuhikuhi inertial a i kekahi. He manaʻo koʻikoʻi kēia e hōʻike ana ʻaʻole pili ka neʻe pili ma waena o nā mea nānā i nā kānāwai kumu o ke kūlohelohe.
Nā Nīnau Laʻana a me ke Kūkākūkā
Nīnau 1: ʻElua mau kaʻaahi, ʻo A lāua ʻo B, e neʻe ana ma nā wikiwiki mau o \(v_A = 30 m/s\) a me \(v_B = 40 m/s\) ma ke kuhikuhi like. Hoʻolei kekahi ohua ma ke kaʻaahi ʻo A i kahi pōpō me ka wikiwiki o \(u = 20 m/s\) i mua o ke kaʻaahi (ma ke kuhikuhi o ka neʻe ʻana o ke kaʻaahi). E helu i ka wikiwiki o ka pōpō e like me ka mea ohua e kū ana ma ke kahua.
Kūkākūkā:
No ka hoʻoholo ʻana i ka wikiwiki o ka pōpō e like me ka mea nānā ma ke kahua, pono mākou e hoʻohui i ka wikiwiki pili o ka pōpō i ka wikiwiki o ke kaʻaahi A. ʻOiai ʻo ka neʻe ʻana a pau ma ke ana hoʻokahi, hiki iā mākou ke hoʻohana i ka hoʻohui vector maʻalahi:
\[
v_{\text{pōpō, kahua}} = v_A + u = 30 \, m/s + 20 \, m/s = 50 \, m/s
\]
No laila, ʻo ka wikiwiki o ka pōpō e like me ka mea nānā ma ke kahua he \(50 m/s\).
Nīnau 2: Aia kekahi astronaut i loko o kahi moku lewa e neʻe ana i ka wikiwiki mau. Inā hoʻā ka astronaut i ke kukui, e ʻike anei kahi mea nānā ma waho o ka moku lewa i kahi wikiwiki ʻokoʻa o ka mālamalama ma mua o ka astronaut i loko o ka moku lewa?
Kūkākūkā:
Wahi a ka postulate mua a Einstein, ua like nā kānāwai o ke kino, me ka wikiwiki o ka mālamalama i loko o kahi hakahaka, ma nā kiʻina kuhikuhi inertial āpau. ʻO ke ʻano kēia, ua mau ka wikiwiki o ka mālamalama a ʻaʻole ia e hilinaʻi i ka wikiwiki o ke kumu a i ʻole ka mea nānā. No laila, e nānā kahi astronaut i loko o ka mokulele a me kahi mea nānā ma waho o ka mokulele i ka wikiwiki like o ka mālamalama, ʻo ia hoʻi \(c \approx 3 \times 10^8 \, m/s\).
ʻO ka Postulate ʻElua a Einstein
ʻO ka lua o ka postulate a Einstein, i ʻike ʻia hoʻi ʻo ke kumumanaʻo o ka invariance o ka wikiwiki o ka mālamalama, ʻōlelo ʻo ia he like ka wikiwiki o ka mālamalama i loko o kahi hakahaka no nā mea nānā āpau, me ka nānā ʻole i ka neʻe pili o ke kumu a mea nānā paha. Hoʻopiʻi kēia postulate i ka ʻike kuʻuna e pono e loli ka wikiwiki o ka mālamalama ma muli o ka wikiwiki o ke kumu a mea nānā paha.
Nā Nīnau Laʻana a me ke Kūkākūkā
Nīnau 3: Hoʻopuka ʻia kahi kukuna o ke kukui mai kahi kukui e neʻe ana ma ka wikiwiki o \(v = 0.6c\) e pili ana i kahi mea nānā paʻa. E helu i ka wikiwiki o ke kukuna o ke kukui e like me ka mea nānā paʻa.
Kūkākūkā:
Wahi a ka postulate lua a Einstein, ʻo ka wikiwiki o ka mālamalama i loko o kahi hakahaka he mau a like no nā mea nānā a pau, me ka nānā ʻole i ka neʻe ʻana ma waena o ka mea nānā a me ke kumu mālamalama. No laila, ʻo ka wikiwiki o kahi kukuna mālamalama e like me ka mea nānā paʻa ʻo \(c\), ʻo ia hoʻi:
\[
v_{\text{light}} = c \approx 3 \times 10^8 \, m/s
\]
Nīnau 4: ʻElua mau mokulele A a me B e neʻe ana kekahi i kekahi me nā wikiwiki \(0.5c\) a me \(0.7c\) e pili ana i kahi mea nānā ma ka Honua. He aha ka wikiwiki o ka mokulele A e like me ka mea nānā ma ka mokulele B?
Kūkākūkā:
I nā hihia e like me kēia, pono mākou e hoʻohana i nā hoʻololi relativistic e hoʻoholo ai i ka wikiwiki pili ma waena o ʻelua mau mea e neʻe kokoke ana i ka wikiwiki o ka mālamalama. ʻO ke ʻano hana wikiwiki relativistic no ʻelua mau mea e hoʻokokoke mai ana:
\[
u' = \frac{u + v}{1 + \frac{uv}{c^2}}
\]
ʻO \(u = 0.5c\) ka wikiwiki o ka moku A e pili ana i ka Honua a ʻo \(v = 0.7c\) ka wikiwiki o ka moku B e pili ana i ka Honua. No ka mea, ke hoʻokokoke mai nei lākou, hoʻokomo mākou i kēia mau waiwai i loko o ke ʻano hana:
\[
u' = \frac{0.5c + 0.7c}{1 + \frac{(0.5c)(0.7c)}{c^2}} = \frac{1.2c}{1 + 0.35} = \frac{1.2c}{1.35} \approx 0.89c
\]
No laila, ʻo ka wikiwiki o ka mokulele A e like me ka mea nānā ma ka mokulele B ma kahi o \(0.89c\).
Ka hopena
Hāʻawi nā postulate mua a me ka lua o Einstein i nā ʻike kumu e kākoʻo ana i ke kumumanaʻo kūikawā o ka relativity. Hoʻomaopopo ka postulate mua he paʻa nā kānāwai o ka physics i nā kiʻina kuhikuhi inertial, e hāʻawi ana i ka like ma waena o nā mea nānā inertial āpau. I kēia manawa, ʻōlelo ka postulate lua he mau ka wikiwiki o ka mālamalama, me ka nānā ʻole i ka neʻe ʻana o ke kumu a mea nānā paha, e wāwahi ana i ke kumumanaʻo o nā wikiwiki pili i ka physics kuʻuna.
ʻAʻole wale ka hoʻomaopopo ʻana i kēia mau manaʻo he mea nui no ke aʻo ʻana i ka physics akā pili pū kekahi i nā noi ʻenehana hou, e like me nā ʻōnaehana hoʻokele GPS, e pono ai nā hoʻoponopono relativistic. Me nā hoʻomaʻamaʻa a me nā laʻana, hiki ke maʻalahi ka hoʻomaopopo ʻana a me ka hoʻopili ʻana i kēia mau manaʻo i nā ʻano like ʻole. Me ka manaʻolana, ua kōkua kēia ʻatikala i ka wehewehe ʻana i nā kumumanaʻo kumu ma hope o ke kumumanaʻo kūikawā o Einstein no ka relativity.
