Mu\u1ed1n bi\u1ebft c\u00f3 xe l\u1eeda t\u1eeb xa ch\u1ea1y \u0111\u1ebfn hay kh\u00f4ng, c\u00f4ng nh\u00e2n \u0111\u01b0\u1eddng s\u1eaft ho\u1eb7c h\u00e0nh kh\u00e1ch th\u01b0\u1eddng \u00e1p tai l\u00ean \u0111\u01b0\u1eddng ray l\u1eafng nghe. N\u1ebfu nghe th\u1ea5y \u00e2m thanh th\u00ec kh\u00f4ng l\u00e2u sau \u0111\u00f3 xe l\u1eeda s\u1ebd x\u00ecnh x\u1ecbch ch\u1ea1y \u0111\u1ebfn. \u0110\u00f3 l\u00e0 v\u00ec sao v\u1eady? Ho\u00e1 ra l\u00e0 c\u00e1i \u0111\u00f3 c\u00f3 quan h\u1ec7 v\u1edbi t\u1ed1c \u0111\u1ed9 truy\u1ec1n \u00e2m thanh.<\/p>\n\n\n\n
Ch\u00fang ta bi\u1ebft r\u1eb1ng, s\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh c\u00f3 m\u1ed9t t\u1ed1c \u0111\u1ed9 nh\u1ea5t \u0111\u1ecbnh. Nh\u01b0ng trong cu\u1ed9c s\u1ed1ng h\u1eb1ng ng\u00e0y, c\u00f3 v\u1ebb nh\u01b0 \u00e2m thanh v\u1eeba ph\u00e1t ra l\u00e0 b\u1ea1n nghe th\u1ea5y ngay. V\u00ed d\u1ee5 nh\u01b0: b\u1ea1n chuy\u1ec7n tr\u00f2 m\u1eb7t \u0111\u1ed1i m\u1eb7t v\u1edbi ng\u01b0\u1eddi trong gia \u0111\u00ecnh, th\u01b0\u1edfng th\u1ee9c ti\u1ebft m\u1ee5c tr\u00ean tivi v.v. \u0110\u00f3 l\u00e0 do ngu\u1ed3n \u00e2m (v\u1eadt th\u1ec3 ph\u00e1t ra \u00e2m thanh) \u1edf r\u1ea5t g\u1ea7n ch\u00fang ta. N\u1ebfu ngu\u1ed3n \u00e2m c\u00e1ch ch\u00fang ta xa m\u1ed9t ch\u00fat, ch\u1eb3ng h\u1ea1n xem m\u00e1y \u0111\u00f3ng c\u1ecdc l\u00e0m vi\u1ec7c \u1edf xa, kh\u00f4ng kh\u00f3 g\u00ec m\u00e0 b\u1ea1n kh\u00f4ng nh\u1eadn th\u1ea5y, sau khi b\u00faa h\u01a1i r\u01a1i xu\u1ed1ng m\u1ed9t ch\u1edbp m\u1eaft th\u00ec b\u1ea1n m\u1edbi nghe th\u1ea5y ti\u1ebfng va \u0111\u1eadp c\u1ee7a b\u00faa h\u01a1i v\u00e0o c\u1ecdc g\u1ed7.<\/p>\n\n\n\n
S\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m thanh ch\u1eb3ng nh\u1eefng c\u00f3 t\u1ed1c \u0111\u1ed9 nh\u1ea5t \u0111\u1ecbnh, m\u00e0 trong m\u00f4i tr\u01b0\u1eddng kh\u00e1c nhau th\u00ec t\u1ed1c \u0111\u1ed9 \u0111\u00f3 c\u0169ng kh\u00e1c nhau. V\u00ed d\u1ee5, trong kh\u00f4ng kh\u00ed \u00e2m thanh c\u00f3 th\u1ec3 truy\u1ec1n v\u00e0o kho\u1ea3ng 340 m\/s; trong n\u01b0\u1edbc n\u00f3 \u0111\u1ea1t t\u1edbi 1440 m\/s, c\u00f2n trong \u0111\u01b0\u1eddng ray th\u00ec nhanh h\u01a1n n\u1eefa, kho\u1ea3ng 5000 m\/s. T\u1ed1c \u0111\u1ed9 xe l\u1eeda n\u00f3i chung l\u00e0 100 – 200 km\/h, c\u00f3 ngh\u0129a l\u00e0 trong kho\u1ea3ng 60 m\/s, ch\u1eadm h\u01a1n r\u1ea5t nhi\u1ec1u so v\u1edbi t\u1ed1c \u0111\u1ed9 truy\u1ec1n \u00e2m trong \u0111\u01b0\u1eddng ray. N\u1ebfu \u1edf c\u00e1ch ch\u00fang ta 5 km c\u00f3 m\u1ed9t \u0111o\u00e0n xe l\u1eeda ch\u1ea1y t\u1edbi, c\u1ea7n ph\u1ea3i c\u00f3 th\u1eddi gian h\u01a1n 80 gi\u00e2y th\u00ec xe l\u1eeda m\u1edbi ch\u1ea1y \u0111\u1ebfn tr\u01b0\u1edbc m\u1eb7t ch\u00fang ta; n\u1ebfu \u0111\u1ee9ng nghe th\u00ec ph\u1ea3i g\u1ea7n 15 gi\u00e2y m\u1edbi nghe th\u1ea5y ti\u1ebfng xe l\u1eeda; c\u00f2n n\u1ebfu \u00e1p tai l\u00ean \u0111\u01b0\u1eddng ray th\u00ec ch\u1ec9 c\u1ea7n kho\u1ea3ng m\u1ed9t gi\u00e2y l\u00e0 c\u00f3 th\u1ec3 nghe th\u1ea5y ti\u1ebfng r\u00ec r\u00ec c\u1ee7a xe l\u1eeda r\u1ed3i.<\/p>\n\n\n\n
H\u01a1n n\u1eefa, c\u01b0\u1eddng \u0111\u1ed9 \u00e2m thanh c\u00f2n b\u1ecb suy gi\u1ea3m trong qu\u00e1 tr\u00ecnh truy\u1ec1n lan. Khi truy\u1ec1n trong kh\u00f4ng kh\u00ed, \u00e2m thanh to\u1ea3 ra t\u1ee9 ph\u00eda xung quanh, suy gi\u1ea3m r\u1ea5t nhanh. Khi b\u1ea1n nghe th\u1ea5y ti\u1ebfng xe l\u1eeda th\u00ec n\u00f3 \u0111\u00e3 \u0111\u1ebfn g\u1ea7n, v\u1ed9i v\u1ed9i v\u00e0ng v\u00e0ng th\u01b0\u1eddng g\u00e2y ra th\u1ea3m ho\u1ea1. Do t\u00e1c d\u1ee5ng \u0111\u1ecbnh h\u01b0\u1edbng c\u1ee7a \u0111\u01b0\u1eddng ray \u0111\u1ed1i v\u1edbi \u00e2m thanh, s\u1ef1 suy gi\u1ea3m c\u1ee7a \u00e2m thanh trong \u0111\u01b0\u1eddng ray di\u1ec5n ra t\u01b0\u01a1ng \u0111\u1ed1i ch\u1eadm. Khi b\u1ea1n \u00e1p tai l\u00ean \u0111\u01b0\u1eddng ray nghe th\u1ea5y \u00e2m thanh c\u1ee7a xe l\u1eeda, b\u1ea1n li\u1ec1n bi\u1ebft xe l\u1eeda \u0111ang ch\u1ea1y t\u1edbi. Khi \u1ea5y n\u00f3 c\u00e1ch ch\u00fang ta c\u00f2n r\u1ea5t xa, b\u1ea1n s\u1ebd \u0111\u01b0\u1ee3c an to\u00e0n.<\/p>\n\n\n\n
V\u1eady n\u1ebfu d\u00f9ng m\u1eaft m\u00e0 nh\u00ecn th\u00ec sao? \u00c1nh s\u00e1ng truy\u1ec1n nhanh h\u01a1n \u00e2m thanh r\u1ea5t nhi\u1ec1u. V\u1edbi kho\u1ea3ng c\u00e1ch 5 km, \u00e1nh s\u00e1ng ch\u1ec9 c\u1ea7n 0,000017 gi\u00e2y l\u00e0 truy\u1ec1n \u0111\u1ebfn r\u1ed3i! Song do c\u00e1c nguy\u00ean nh\u00e2n nh\u01b0 s\u1ef1 che khu\u1ea5t c\u1ee7a \u0111\u01b0\u1eddng ch\u00e2n tr\u1eddi, che ph\u1ee7 c\u1ee7a l\u1edbp s\u01b0\u01a1ng v\u00e0 m\u00e0n b\u1ee5i, s\u1ef1 u\u1ed1n kh\u00fac c\u1ee7a \u0111\u01b0\u1eddng ray, c\u1ea3n tr\u1edf c\u1ee7a c\u00f4ng tr\u00ecnh ki\u1ebfn tr\u00fac, d\u00e3y n\u00fai, kh\u00f3m c\u00e2y, v.v. n\u00ean ch\u00fang ta kh\u00f4ng sao c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y r\u00f5 xe l\u1eeda \u1edf n\u01a1i xa ngo\u00e0i 5 km. Cho n\u00ean, mu\u1ed1n ph\u00e1n \u0111o\u00e1n c\u00f3 xe l\u1eeda t\u1eeb xa ch\u1ea1y \u0111\u1ebfn hay kh\u00f4ng th\u00ec ph\u01b0\u01a1ng ph\u00e1p \u0111\u01a1n gi\u1ea3n d\u1ec5 l\u00e0m nh\u1ea5t l\u00e0 \u00e1p tai l\u00ean \u0111\u01b0\u1eddng ray l\u1eafng nghe th\u1eed xem.<\/p>\n\n\n\n
T\u1eeb kho\u00e1: Xe l\u1eeda; \u0110\u01b0\u1eddng ray; T\u1ed1c \u0111\u1ed9 \u00e2m thanh; S\u1ef1 lan truy\u1ec1n c\u1ee7a \u00e2m<\/p>\n\n\n\n
<\/p>\n\n\n\n\n\n\n","protected":false},"excerpt":{"rendered":"
Mu\u1ed1n bi\u1ebft c\u00f3 xe l\u1eeda t\u1eeb xa ch\u1ea1y \u0111\u1ebfn hay kh\u00f4ng, c\u00f4ng nh\u00e2n \u0111\u01b0\u1eddng s\u1eaft ho\u1eb7c h\u00e0nh kh\u00e1ch th\u01b0\u1eddng \u00e1p tai l\u00ean \u0111\u01b0\u1eddng ray l\u1eafng nghe. N\u1ebfu nghe th\u1ea5y \u00e2m thanh th\u00ec kh\u00f4ng l\u00e2u sau \u0111\u00f3 xe l\u1eeda s\u1ebd x\u00ecnh x\u1ecbch ch\u1ea1y \u0111\u1ebfn. \u0110\u00f3 l\u00e0 v\u00ec sao v\u1eady? Ho\u00e1 ra l\u00e0 c\u00e1i \u0111\u00f3 c\u00f3 quan […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_disable_autopaging":false},"categories":[15,7],"tags":[],"class_list":["post-5636","post","type-post","status-publish","format-standard","hentry","category-hoi-dap-khoa-hoc","category-vat-ly"],"_links":{"self":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5636","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/comments?post=5636"}],"version-history":[{"count":0,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/posts\/5636\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/media?parent=5636"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/categories?post=5636"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vietlearn.org\/kien-thuc\/wp-json\/wp\/v2\/tags?post=5636"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}