{"common":{"save":0,"post_id":"8860","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"8345","mon_id":"1158790","chapter_id":"1159899","post_id":"8860","question":"<p>Lò xo có \u0111\u1ed9 c\u1ee9ng k, m\u1ed9t \u0111\u1ea7u treo vào \u0111i\u1ec3m c\u1ed1 \u0111\u1ecbnh, \u0111\u1ea7u còn l\u1ea1i \u0111\u01b0\u1ee3c g\u1eafn vào v\u1eadt có kh\u1ed1i l\u01b0\u1ee3ng m. Khi v\u1eadt cân b\u1eb1ng thì h\u1ec7 th\u1ee9c nào sau \u0111ây \u0111\u01b0\u1ee3c nghi\u1ec7m \u0111u\u0301ng?<\/p>","options":["<strong>A.<\/strong> <span class=\"math-tex\">$\\dfrac{k}{\\Delta l}=\\dfrac{m}{g}$<\/span>","<strong>B.<\/strong> <span class=\"math-tex\">$mg=k\\Delta l$<\/span>","<strong>C.<\/strong> <span class=\"math-tex\">$\\dfrac{g}{\\Delta l}=\\dfrac{m}{k}$<\/span>","<strong>D.<\/strong> <span class=\"math-tex\">$k=\\dfrac{\\Delta l}{mg}$<\/span>"],"correct":"2","level":"3","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> <span class=\"math-tex\">$mg=k\\Delta l$<\/span>.<\/span><\/p><p>Khi lò xo cân b\u1eb1ng, ta có: <span class=\"math-tex\">$F_{\u0111h}=P$<\/span> hay <span class=\"math-tex\">$mg=k\\Delta l$<\/span>.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-04-14 08:26:25","option_type":"math","len":0},{"id":"8347","mon_id":"1158790","chapter_id":"1159899","post_id":"8860","question":"<p>M\u1ed9t lò xo có chi\u1ec1u dài t\u1ef1 nhiên b\u1eb1ng 22 (cm). Lò xo \u0111\u01b0\u1ee3c treo th\u1eb3ng \u0111\u1ee9ng, m\u1ed9t \u0111\u1ea7u gi\u1eef c\u1ed1 \u0111\u1ecbnh, còn \u0111\u1ea7u kia g\u1eafn m\u1ed9t v\u1eadt n\u1eb7ng. Khi \u1ea5y lò xo dài 27 (cm), cho bi\u1ebft \u0111\u1ed9 c\u1ee9ng lò xo là 100 (N\/m). \u0110\u1ed9 l\u1edbn l\u1ef1c \u0111àn h\u1ed3i b\u1eb1ng<\/p>","options":["<strong>A.<\/strong> 500 N","<strong>B.<\/strong> 5 N","<strong>C.<\/strong> 20 N","<strong>D.<\/strong> 50 N"],"correct":"2","level":"3","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> 5 N.<\/span><\/p><p>\u0110\u1ed9 bi\u1ebfn d\u1ea1ng c\u1ee7a lò xo: <span class=\"math-tex\">$\\Delta l=27-22=5(cm)=0,05(m)$<\/span>.<br \/>\u0110\u1ed9 l\u1edbn l\u1ef1c \u0111àn h\u1ed3i b\u1eb1ng: <span class=\"math-tex\">$F_{\u0111h}=k.|\\Delta l|=100.0,05=5(N)$<\/span>.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-04-14 08:29:18","option_type":"txt","len":0},{"id":"8349","mon_id":"1158790","chapter_id":"1159899","post_id":"8860","question":"<p>Ph\u1ea3i treo m\u1ed9t v\u1eadt có kh\u1ed1i l\u01b0\u1ee3ng b\u1eb1ng bao nhiêu vào lò xo có \u0111\u1ed9 c\u1ee9ng<br \/>k = 100 N\/m \u0111\u1ec3 lò xo dãn ra \u0111\u01b0\u1ee3c 10 cm? L\u1ea5y g = 10 m\/s².<\/p>","options":["<strong>A.<\/strong> 1 kg","<strong>B.<\/strong> 10 kg","<strong>C.<\/strong> 100 kg","<strong>D.<\/strong> 1000 kg"],"correct":"1","level":"3","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>A.<\/strong> 1 kg.<\/span><\/p><p>Khi lò xo cân b\u1eb1ng, ta có: <\/p><p><span class=\"math-tex\">$F_{\u0111h}=P$<\/span> hay <span class=\"math-tex\">$k\\Delta l=mg$<\/span> ⇒ <span class=\"math-tex\">$m=k\\Delta l:g=100.0,1:10=1(kg)$<\/span>.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-04-14 08:31:55","option_type":"txt","len":0}]}
