{"id":1650,"date":"2013-08-15T13:26:26","date_gmt":"2013-08-15T11:26:26","guid":{"rendered":"http:\/\/www.zsvltava.cz\/fyzika\/?p=1650"},"modified":"2025-04-10T09:29:55","modified_gmt":"2025-04-10T07:29:55","slug":"sila-otazky-k-opakovani","status":"publish","type":"post","link":"https:\/\/www.zsvltava.cz\/fyzika\/?p=1650","title":{"rendered":"S\u00edla &#8211; ot\u00e1zky k opakov\u00e1n\u00ed"},"content":{"rendered":"<ol style=\"font-weight: bold;\">\n<li>Co je to s\u00edla?<\/li>\n<li>Popi\u0161, jak s\u00edlu zn\u00e1zor\u0148ujeme.<\/li>\n<li>Jak\u00e9 2 \u00fa\u010dinky m\u016f\u017ee m\u00edt p\u016fsoben\u00ed s\u00edly?<\/li>\n<li>Co je to gravita\u010dn\u00ed s\u00edla?<\/li>\n<li>Jak vypo\u010d\u00edt\u00e1me gravita\u010dn\u00ed s\u00edlu?<\/li>\n<li>Kterou s\u00edlu naz\u00fdv\u00e1me tlakovou?<\/li>\n<li>Na \u010dem z\u00e1vis\u00ed tlakov\u00e1 s\u00edla?<\/li>\n<\/ol>\n<h2>Spr\u00e1vn\u00e9 odpov\u011bdi<\/h2>\n<h3>Co je to s\u00edla?<\/h3>\n<p><a href=\"\/fyzika\/?p=983\">S\u00edla<\/a> je fyzik\u00e1ln\u00ed veli\u010dina, kter\u00e1 popisuje vz\u00e1jemn\u00e9 p\u016fsoben\u00ed mezi t\u011blesy. M\u016f\u017ee zp\u016fsobit zm\u011bnu pohybu t\u011blesa (zrychlen\u00ed, zpomalen\u00ed, zm\u011bnu sm\u011bru) nebo jeho deformaci. Jednotkou s\u00edly je newton (N).<\/p>\n<h3>Jak s\u00edlu zn\u00e1zor\u0148ujeme?<\/h3>\n<p>S\u00edlu zn\u00e1zor\u0148ujeme pomoc\u00ed \u0161ipky, kter\u00e1 se naz\u00fdv\u00e1 vektor s\u00edly. \u0160ipka m\u00e1:<\/p>\n<ul>\n<li>Sm\u011br, kter\u00fd ur\u010duje, kam s\u00edla p\u016fsob\u00ed.<\/li>\n<li>Velikost, vyj\u00e1d\u0159enou d\u00e9lkou \u0161ipky (v m\u011b\u0159\u00edtku).<\/li>\n<li>P\u016fsobi\u0161t\u011b, co\u017e je bod, kde s\u00edla na t\u011bleso p\u016fsob\u00ed.<\/li>\n<\/ul>\n<h3>Jak\u00e9 2 \u00fa\u010dinky m\u016f\u017ee m\u00edt p\u016fsoben\u00ed s\u00edly?<\/h3>\n<ol>\n<li>Pohybov\u00fd \u00fa\u010dinek \u2013 s\u00edla m\u016f\u017ee zm\u011bnit rychlost nebo sm\u011br pohybu t\u011blesa (nap\u0159\u00edklad zrychlit, zpomalit, zastavit nebo oto\u010dit).<\/li>\n<li>Deforma\u010dn\u00ed \u00fa\u010dinek \u2013 s\u00edla m\u016f\u017ee zm\u011bnit tvar t\u011blesa (nap\u0159\u00edklad pru\u017en\u00e1 deformace p\u0159i stla\u010den\u00ed pru\u017einy nebo trval\u00e1 deformace p\u0159i ohnut\u00ed kovu).<\/li>\n<\/ol>\n<h3>Co je to gravita\u010dn\u00ed s\u00edla?<\/h3>\n<p><a href=\"\/fyzika\/?p=1619\">Gravita\u010dn\u00ed s\u00edla<\/a> je s\u00edla, kterou Zem\u011b (nebo jin\u00e9 hmotn\u00e9 t\u011bleso) p\u0159itahuje jin\u00e1 t\u011blesa. Je to p\u0159\u00edklad p\u0159ita\u017eliv\u00e9 s\u00edly a p\u016fsob\u00ed sm\u011brem k st\u0159edu Zem\u011b. Tuto s\u00edlu poci\u0165ujeme jako \u201ev\u00e1hu\u201c t\u011blesa.<\/p>\n<h3>Jak vypo\u010d\u00edt\u00e1me gravita\u010dn\u00ed s\u00edlu?<\/h3>\n<p>Gravita\u010dn\u00ed s\u00edla F<sub>g<\/sub> se vypo\u010d\u00edt\u00e1 podle vztahu: <strong>F<sub>g<\/sub> = m \u22c5 g<\/strong><\/p>\n<p>F<sub>g<\/sub>\u200b &#8211; gravita\u010dn\u00ed s\u00edla (v newtonech, N),<br \/>\nm &#8211; hmotnost t\u011blesa (v kilogramech, kg),<br \/>\ng &#8211; gravita\u010dn\u00ed zrychlen\u00ed (p\u0159ibli\u017en\u011b 9,81 m\/s\u00b2 na Zemi).<br \/>\n\u200b<\/p>\n<h3>Kterou s\u00edlu naz\u00fdv\u00e1me tlakovou?<\/h3>\n<p>Tlakov\u00e1 s\u00edla je s\u00edla, kter\u00e1 p\u016fsob\u00ed kolmo na plochu t\u011blesa. Tlakov\u00e1 s\u00edla je odpov\u011bdn\u00e1 za vznik tlaku, nap\u0159\u00edklad s\u00edla p\u016fsob\u00edc\u00ed na podlahu pod nohama \u010dlov\u011bka.<\/p>\n<h3>Na \u010dem z\u00e1vis\u00ed tlakov\u00e1 s\u00edla?<\/h3>\n<p>Tlakov\u00e1 s\u00edla z\u00e1vis\u00ed na:<\/p>\n<ul>\n<li>Velikosti p\u016fsob\u00edc\u00ed s\u00edly \u2013 \u010d\u00edm v\u011bt\u0161\u00ed s\u00edla, t\u00edm v\u011bt\u0161\u00ed tlak.<\/li>\n<li>Velikosti plochy, na kterou s\u00edla p\u016fsob\u00ed \u2013 p\u0159i stejn\u00e9 s\u00edle bude tlak v\u011bt\u0161\u00ed, pokud je plocha men\u0161\u00ed (nap\u0159\u00edklad tlak pod tenk\u00fdmi podpatky je v\u011bt\u0161\u00ed ne\u017e pod \u0161irok\u00fdmi botami).<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Co je to s\u00edla? Popi\u0161, jak s\u00edlu zn\u00e1zor\u0148ujeme. Jak\u00e9 2 \u00fa\u010dinky m\u016f\u017ee m\u00edt p\u016fsoben\u00ed s\u00edly? Co je to gravita\u010dn\u00ed s\u00edla? Jak vypo\u010d\u00edt\u00e1me gravita\u010dn\u00ed s\u00edlu? Kterou &#8230;. <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[35,59],"tags":[89],"class_list":["post-1650","post","type-post","status-publish","format-standard","hentry","category-sila","category-tlak","tag-otazky-a-odpovedi"],"_links":{"self":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/1650","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=1650"}],"version-history":[{"count":0,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=\/wp\/v2\/posts\/1650\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1650"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1650"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zsvltava.cz\/fyzika\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1650"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}