{"id":4291,"date":"2021-02-21T08:23:03","date_gmt":"2021-02-21T06:23:03","guid":{"rendered":"http:\/\/www.zsvltava.cz\/fyzika\/?p=4291"},"modified":"2025-04-10T09:36:51","modified_gmt":"2025-04-10T07:36:51","slug":"priklad-s-vodou-a-valeckem","status":"publish","type":"post","link":"https:\/\/www.zsvltava.cz\/fyzika\/?p=4291","title":{"rendered":"P\u0159\u00edklad s vodou a v\u00e1le\u010dkem"},"content":{"rendered":"

Do 1 litru vrouc\u00ed vody vhod\u00edme kovov\u00fd 100g v\u00e1le\u010dek, kter\u00fd jsme pr\u00e1v\u011b vyt\u00e1hli z mraz\u00e1ku. Jak se zm\u011bn\u00ed teplota vody?<\/p>\n

\u0158e\u0161en\u00ed<\/h2>\n

T\u011bleso:<\/p>\n

m1<\/sub> = 100 g = 0,1 kg
\nt1<\/sub> = -20\u00b0C
\nc1<\/sub> = 450 J\/kg\u00b7\u00b0C<\/p>\n

Voda:<\/p>\n

t2<\/sub> = 100 \u00b0C
\nc2<\/sub> = 4180 J\/kg\u00b7\u00b0C
\nV = 1 litr = 1 dm3<\/sup> = 0,001 m3<\/sup><\/p>\n

m2<\/sub> = ρ . V = 1000 kg\/m3<\/sup> . 0,001 m3<\/sup> = 1 kg<\/p>\n

V\u00fdsledn\u00e1 teplota<\/p>\n

t = ? \u00b0C<\/p>\n

\n

Vych\u00e1z\u00edme ze vztahu pro v\u00fdpo\u010det tepla:<\/p>\n

Q = m . c . (t2<\/sub> – t1<\/sub>)<\/p>\n

M\u00e1me ale tzv. tepelnou soustavu. Teplej\u0161\u00ed t\u011bleso bude odevzd\u00e1vat teplo chladn\u011bj\u0161\u00edmu. A to tak dlouho, dokud se teploty nevyrovnaj\u00ed na v\u00fdslednou teplotu t<\/em><\/p>\n

m1<\/sub> . c1<\/sub> . (t – t1<\/sub>) = m2<\/sub> . c2<\/sub> . (t2<\/sub> – t)<\/p>\n

0,1 kg . 450 J\/kg\u00b7\u00b0C . (t – (-20\u00b0C)) = 1 kg . 4180 J\/kg\u00b7\u00b0C . (100\u00b0C – t)
\n45 J\/\u00b0C . (t + 20\u00b0C) = 4180 J\/\u00b0C . (100\u00b0C – t)<\/p>\n

45 . t + 900 = 418000 – 4180 . t
\n4225 t = 417100<\/p>\n

t = 98,7 \u00b0C<\/p>\n

Teplota vody klesne p\u0159ibli\u017en\u011b o 1,3 \u00b0C.<\/p>\n","protected":false},"excerpt":{"rendered":"

Do 1 litru vrouc\u00ed vody vhod\u00edme kovov\u00fd 100g v\u00e1le\u010dek, kter\u00fd jsme pr\u00e1v\u011b vyt\u00e1hli z mraz\u00e1ku. Jak se zm\u011bn\u00ed teplota vody? \u0158e\u0161en\u00ed T\u011bleso: m1 = 100 …. <\/p>\n","protected":false},"author":1,"featured_media":4293,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[43,50],"tags":[23],"class_list":["post-4291","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-priklady-pro-8-rocnik","category-teplo","tag-reseny-priklad"],"_links":{"self":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/4291","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4291"}],"version-history":[{"count":0,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/4291\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/media\/4293"}],"wp:attachment":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4291"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4291"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4291"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}