Chú ý: Để đảm bảo quyền lợi và bảo vệ tài khoản của mình
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{"common":{"save":0,"post_id":"8608","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"7931","mon_id":"1158790","chapter_id":"1159772","post_id":"8608","question":"<p>\u0110áp án nào sau \u0111ây là <strong>\u0111úng?<\/strong><\/p>","options":["<strong>A.<\/strong> L\u1ef1c là \u0111\u1ea1i l\u01b0\u1ee3ng vect\u01a1 nên công c\u0169ng là \u0111\u1ea1i l\u01b0\u1ee3ng vect\u01a1.","<strong>B.<\/strong> Trong chuy\u1ec3n \u0111\u1ed9ng tròn, l\u1ef1c h\u01b0\u1edbng tâm th\u1ef1c hi\u1ec7n công vì có c\u1ea3 hai y\u1ebfu t\u1ed1: l\u1ef1c và \u0111\u1ed9 d\u1eddi c\u1ee7a v\u1eadt.","<strong>C. <\/strong>Công c\u1ee7a l\u1ef1c là \u0111\u1ea1i l\u01b0\u1ee3ng vô h\u01b0\u1edbng và có giá tr\u1ecb \u0111\u1ea1i s\u1ed1.","<strong>D.<\/strong> M\u1ed9t v\u1eadt chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng \u0111\u1ec1u, công c\u1ee7a h\u1ee3p l\u1ef1c là khác không vì có \u0111\u1ed9 d\u1eddi c\u1ee7a v\u1eadt."],"correct":"3","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>C. <\/strong>Công c\u1ee7a l\u1ef1c là \u0111\u1ea1i l\u01b0\u1ee3ng vô h\u01b0\u1edbng và có giá tr\u1ecb \u0111\u1ea1i s\u1ed1.<\/span><\/p><p>A – sai, l\u1ef1c là \u0111\u1ea1i l\u01b0\u1ee3ng vecto còn công là \u0111\u1ea1i l\u01b0\u1ee3ng vô h\u01b0\u1edbng.<\/p><p>B – sai, trong chuy\u1ec3n \u0111\u1ed9ng tròn, l\u1ef1c h\u01b0\u1edbng tâm có h\u01b0\u1edbng vào tâm qu\u1ef9 \u0111\u1ea1o và có ph\u01b0\u01a1ng vuông góc v\u1edbi vect\u01a1 v\u1eadn t\u1ed1c t\u1ea1i m\u1ed7i \u0111i\u1ec3m trên qu\u1ef9 \u0111\u1ea1o. L\u1ef1c h\u01b0\u1edbng tâm trong tr\u01b0\u1eddng h\u1ee3p này không th\u1ef1c hi\u1ec7n công.<\/p><p>C – \u0111úng.<\/p><p>D – sai, khi v\u1eadt chuy\u1ec3n \u0111\u1ed9ng th\u1eb3ng \u0111\u1ec1u thì h\u1ee3p l\u1ef1c tác d\u1ee5ng lên v\u1eadt b\u1eb1ng 0 nên công c\u1ee7a h\u1ee3p l\u1ef1c c\u0169ng b\u1eb1ng 0.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-03-16 14:14:26","option_type":"txt","len":3},{"id":"7934","mon_id":"1158790","chapter_id":"1159772","post_id":"8608","question":"<p>M\u1ed9t ng\u01b0\u1eddi kéo m\u1ed9t hòm g\u1ed7 tr\u01b0\u1ee3t trên sàn nhà b\u1eb1ng m\u1ed9t dây có ph\u01b0\u01a1ng h\u1ee3p v\u1edbi ph\u01b0\u01a1ng ngang m\u1ed9t góc 60°. L\u1ef1c tác d\u1ee5ng lên dây b\u1eb1ng 150 N. B\u1ecf qua ma sát. Công c\u1ee7a l\u1ef1c \u0111ó th\u1ef1c hi\u1ec7n \u0111\u01b0\u1ee3c khi hòm tr\u01b0\u1ee3t \u0111i \u0111\u01b0\u1ee3c 10 m là:<\/p>","options":["<strong>A.<\/strong> 1275 J.","<strong>B.<\/strong> 750 J.","<strong>C.<\/strong> 6000 J.","<strong>D.<\/strong> 1500 J."],"correct":"2","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>B.<\/strong> 750 J.<\/span><\/p><p>Công c\u1ee7a l\u1ef1c \u0111ó là: A = F.s.cosα = 150.10.cos60° = 750 J.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-03-16 14:30:12","option_type":"txt","len":0},{"id":"7935","mon_id":"1158790","chapter_id":"1159772","post_id":"8608","question":"<p>Mô\u0323t vâ\u0323t 5,5 kg \u0111\u01b0\u01a1\u0323c \u0111\u0103\u0323t trên m\u0103\u0323t ph\u0103\u0309ng nghiêng. Chiê\u0300u da\u0300i cu\u0309a m\u0103\u0323t ph\u0103\u0309ng nghiêng la\u0300 10 m, chiê\u0300u cao là 5 m. Lâ\u0301y g = 10 m\/s². Công cu\u0309a tro\u0323ng l\u01b0\u0323c khi vâ\u0323t tr\u01b0\u01a1\u0323t t\u01b0\u0300 \u0111i\u0309nh xuô\u0301ng chân m\u0103\u0323t ph\u0103\u0309ng nghiêng co\u0301 \u0111ô\u0323 l\u01a1\u0301n la\u0300:<\/p><p><span class=\"svgedit\"><svg height=\"130\" width=\"220\"> <g><title><\/title><rect fill=\"#fff\" height=\"132\" id=\"canvas_background\" width=\"222\" x=\"-1\" y=\"-1\"><\/rect> <g display=\"none\" height=\"100%\" id=\"canvasGrid\" overflow=\"visible\" width=\"100%\" x=\"0\" y=\"0\"> <rect fill=\"url(#gridpattern)\" height=\"100%\" stroke-width=\"0\" width=\"100%\" x=\"0\" y=\"0\"><\/rect> <\/g> <\/g> <g><title><\/title><g id=\"svg_6\"> <path d=\"m46.19089,124.33861l0,-97l169.99999,97l-169.99999,0z\" fill=\"#bf5f00\" id=\"svg_1\" stroke=\"#000\" stroke-width=\"1.5\"><\/path> <ellipse cx=\"48.38281\" cy=\"15.49609\" fill=\"#ffff00\" id=\"svg_3\" rx=\"11\" ry=\"11\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"1.5\"><\/ellipse> <text fill=\"#000000\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_4\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"1.38281\" xml:space=\"preserve\" y=\"75.49609\">5 m<\/text> <text fill=\"#000000\" font-family=\"Helvetica, Arial, sans-serif\" font-size=\"24\" id=\"svg_5\" stroke=\"#000\" stroke-opacity=\"null\" stroke-width=\"0\" text-anchor=\"start\" x=\"121.38281\" xml:space=\"preserve\" y=\"67.49609\">10 m<\/text> <\/g> <\/g> <\/svg><\/span><\/p>","options":["<strong>A.<\/strong> 270 J.","<strong>B.<\/strong> 220 J.","<strong>C.<\/strong> 275 J.","<strong>D.<\/strong> 260 J."],"correct":"3","level":"2","hint":"","answer":"<p>Ch\u1ecdn <span style=\"color:#16a085;\"><strong>C.<\/strong> 275 J.<\/span><\/p><p>Công cu\u0309a tro\u0323ng l\u01b0\u0323c khi vâ\u0323t tr\u01b0\u01a1\u0323t t\u01b0\u0300 \u0111\u1ec9nh xuô\u0301ng chân m\u0103\u0323t ph\u0103\u0309ng nghiêng co\u0301 \u0111ô\u0323 l\u01a1\u0301n la\u0300<\/p><p><span class=\"math-tex\">$A=P.s.\\cos(\\overrightarrow{P},\\overrightarrow{s})=m.g.s.\\dfrac{h}{s}=5,5.10.10.\\dfrac{5}{10}=275J$<\/span>.<\/p>","type":"choose","extra_type":"classic","user_id":"131","test":"0","date":"2025-03-16 14:34:54","option_type":"txt","len":0}]}