Cơ năng và định luật bảo toàn cơ năng (trung bình)

Home Lớp 10 Vật lý 10 - Sách kết nối tri thức Bài 26: Cơ năng và định luật bảo toàn cơ năngBài tập trung bình

{"common":{"save":0,"post_id":"6409","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"6532","mon_id":"1158790","chapter_id":"1159772","post_id":"6409","question":"M\u1ed9t viên bi kh\u1ed1i l\u01b0\u1ee3ng m chuy\u1ec3n \u0111\u1ed9ng ngang không ma sát v\u1edbi v\u1eadn t\u1ed1c $v_0$<\/span> r\u1ed3i \u0111i lên m\u1eb7t ph\u1eb3ng nghiêng có góc nghiêng $\\alpha$<\/span>  so v\u1edbi ph\u01b0\u01a1ng ngang, bi \u0111\u1ea1t \u0111\u1ed9 cao c\u1ef1c \u0111\u1ea1i H sau khi \u0111i \u0111\u01b0\u1ee3c quãng \u0111\u01b0\u1eddng $s$<\/span>. Ph\u01b0\u01a1ng trình nào sau \u0111ây di\u1ec5n t\u1ea3 \u0111\u1ecbnh lu\u1eadt b\u1ea3o toàn c\u01a1 n\u0103ng c\u1ee7a h\u1ec7<\/p><svg height=\"86\" width=\"218\" xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\"> <g><title><\/title><rect fill=\"#fff\" height=\"88\" id=\"canvas_background\" width=\"220\" 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><image height=\"100\" id=\"svg_1\" width=\"222\" x=\"-0.99999\" xlink:href=\"data:image\/png;base64,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\" y=\"-3.99999\"><\/image> <\/g> <\/svg><\/span><\/p>","options":["A. <\/strong>$\\frac{mv_0^2}{2}= mgH$<\/span>","B. <\/strong>$\\frac{mv_0^2}{2} - mgs= 0$<\/span>","C. <\/strong>$mgs. cos\\alpha = \\frac{mv_0^2}{2}$<\/span>","D. <\/strong>$\\frac{mv_0^2}{2} + mgs= 0$<\/span>"],"correct":"1","level":"2","hint":"","answer":"Ch\u1ecdn g\u1ed1c th\u1ebf n\u0103ng trùng v\u1edbi m\u1eb7t ph\u1eb3ng n\u1eb1m ngang. T\u1ea1i v\u1ecb trí b\u1eaft \u0111\u1ea7u chuy\u1ec3n \u0111\u1ed9ng, c\u01a1 n\u0103ng $W_1$<\/span> ch\u1ec9 có \u0111\u1ed9ng n\u0103ng. T\u1ea1i v\u1ecb trí \u0111\u1ea1t \u0111\u1ed9 cao c\u1ef1c \u0111\u1ea1i H, c\u01a1 n\u0103ng $W_2$<\/span> ch\u1ec9 có th\u1ebf n\u0103ng. Do không có ma sát nên c\u01a1 n\u0103ng \u0111\u01b0\u1ee3c b\u1ea3o toàn, ta có:  $W_1= W_2 \\iff W_{d1}= W_{t2} \\implies \\frac{1}{2}mv_0^2= mgH$<\/span> \u0110áp án \u0111úng: A. $\\frac{mv_0^2}{2}= mgH$<\/span><\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"149","test":"0","date":"2023-03-30 12:57:46","option_type":"math","len":0},{"id":"6533","mon_id":"1158790","chapter_id":"1159772","post_id":"6409","question":"Mô\u0323t vâ\u0323t khô\u0301i l\u01b0\u01a1\u0323ng 200g \u0111\u01b0\u01a1\u0323c tha\u0309 r\u01a1i t\u01b0\u0323 do t\u01b0\u0300 vi\u0323 tri\u0301 co\u0301 thê\u0301 n\u0103ng b\u0103\u0300ng 40J, bo\u0309 qua mo\u0323i ma sa\u0301t, lâ\u0301y $g= 10m\/s^2$<\/span> . \u0110ô\u0323 cao cu\u0309a vâ\u0323t khi thê\u0301 n\u0103ng b\u0103\u0300ng ba lâ\u0300n \u0111ô\u0323ng n\u0103ng b\u1eb1ng<\/p>","options":["A.<\/strong> 5 m.","B. <\/strong>10 m.","C. <\/strong>15 m.","D. <\/strong>20 m."],"correct":"3","level":"2","hint":"T\u1ea1i v\u1ecb trí th\u1ea3 r\u01a1i, c\u01a1 n\u0103ng $W_1$<\/span> bao g\u1ed3m th\u1ebf n\u0103ng. T\u1ea1i v\u1ecb trí \u0111\u1ed9 cao b\u1eb1ng 3 l\u1ea7n th\u1ebf n\u0103ng, c\u01a1 n\u0103ng $W_2$<\/span> bao g\u1ed3m c\u1ea3 \u0111\u1ed9ng n\u0103ng và th\u1ebf n\u0103ng. Do b\u1ecf qua ma sát nên c\u01a1 n\u0103ng \u0111\u01b0\u1ee3c b\u1ea3o toàn. Áp d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o toàn c\u01a1 n\u0103ng \u0111\u1ec3 tìm.<\/p>","answer":"T\u1ea1i v\u1ecb trí th\u1ea3 r\u01a1i, c\u01a1 n\u0103ng $W_1$<\/span> bao g\u1ed3m th\u1ebf n\u0103ng. T\u1ea1i v\u1ecb trí \u0111\u1ed9 cao b\u1eb1ng 3 l\u1ea7n th\u1ebf n\u0103ng, c\u01a1 n\u0103ng $W_2$<\/span> bao g\u1ed3m c\u1ea3 \u0111\u1ed9ng n\u0103ng và th\u1ebf n\u0103ng. Do b\u1ecf qua ma sát nên c\u01a1 n\u0103ng \u0111\u01b0\u1ee3c b\u1ea3o toàn. Áp d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o toàn c\u01a1 n\u0103ng, ta có:  $W_1=W_2 \\iff W_t1= W_{d2} + W_{t2}= \\frac{1}{3} W_{t2} + W_{t2} = \\frac{4}{3}W_{t2} = \\frac{4}{3} mgh_2$<\/span>  $\\Rightarrow 40= \\frac{4}{3}.0,2.10.h_2 \\Rightarrow h_2= 15(m)$<\/span> \u0110áp án \u0111úng: C. 15 m.<\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"149","test":"0","date":"2023-03-30 13:07:53","option_type":"txt","len":0},{"id":"6534","mon_id":"1158790","chapter_id":"1159772","post_id":"6409","question":"M\u1ed9t v\u1eadn \u0111\u1ed9ng viên n\u1eb7ng 650N th\u1ea3 mình r\u01a1i t\u1ef1 do t\u1eeb c\u1ea7u nh\u1ea3y \u1edf \u0111\u1ed9 cao 10m xu\u1ed1ng n\u01b0\u1edbc. L\u1ea5y g = 10 m\/$s^2$<\/span>, v\u1eadn t\u1ed1c c\u1ee7a ng\u01b0\u1eddi \u0111ó \u1edf \u0111\u1ed9 cao 5m so v\u1edbi m\u1eb7t n\u01b0\u1edbc và khi ch\u1ea1m n\u01b0\u1edbc là<\/p>","options":["A. <\/strong>10 m\/s; 14,14 m\/s.","B. <\/strong>5 m\/s; 10 m\/s.","C. <\/strong>8 m\/s; 12,2 m\/s.","D. <\/strong>8 m\/s; 11,6 m\/s."],"correct":"1","level":"2","hint":"Ch\u1ecdn m\u1ed1c th\u1ebf n\u0103ng t\u1ea1i m\u1eb7t n\u01b0\u1edbc. C\u01a1 n\u0103ng $W_1$<\/span> c\u1ee7a v\u1eadn \u0111\u1ed9ng viên t\u1ea1i \u0111\u1ed9 cao 5 m so v\u1edbi m\u1eb7t n\u01b0\u1edbc bao g\u1ed3m \u0111\u1ed9ng n\u0103ng và th\u1ebf n\u0103ng. C\u01a1 n\u0103ng $W_2$<\/span> c\u1ee7a v\u1eadn \u0111\u1ed9ng viên khi ch\u1ea1m n\u01b0\u1edbc ch\u1ec9 có \u0111\u1ed9ng n\u0103ng (th\u1ebf n\u0103ng b\u1eb1ng 0 do trùng m\u1ed1c th\u1ebf n\u0103ng). Áp d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o toàn c\u01a1 n\u0103ng.<\/p>","answer":"Kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a v\u1eadn \u0111\u1ed9ng viên: $m= \\frac{P}{g}= \\frac{650}{10}= 65(kg)$<\/span> C\u01a1 n\u0103ng c\u1ee7a v\u1eadn \u0111\u1ed9ng viên t\u1ea1i \u0111\u1ed9 cao 10 m:  $W= P.h= 650.10= 6500(J)$<\/span> Ch\u1ecdn m\u1ed1c th\u1ebf n\u0103ng t\u1ea1i m\u1eb7t n\u01b0\u1edbc. C\u01a1 n\u0103ng $W_1$<\/span> c\u1ee7a v\u1eadn \u0111\u1ed9ng viên t\u1ea1i \u0111\u1ed9 cao 5 m so v\u1edbi m\u1eb7t n\u01b0\u1edbc bao g\u1ed3m \u0111\u1ed9ng n\u0103ng và th\u1ebf n\u0103ng. C\u01a1 n\u0103ng $W_2$<\/span> c\u1ee7a v\u1eadn \u0111\u1ed9ng viên khi ch\u1ea1m n\u01b0\u1edbc ch\u1ec9 có \u0111\u1ed9ng n\u0103ng (th\u1ebf n\u0103ng b\u1eb1ng 0 do trùng m\u1ed1c th\u1ebf n\u0103ng). Áp d\u1ee5ng \u0111\u1ecbnh lu\u1eadt b\u1ea3o toàn c\u01a1 n\u0103ng, ta có:  $W= W_1 \\iff W= W_{d1} + W_{t1} \\iff W= \\frac{1}{2}mv_1^2 +mgh_1$<\/span>  $\\Rightarrow 6500= \\frac{1}{2}.65.v_1^2+ 65.10.5 \\iff v_1= 10(m\/s)$<\/span>  $W= W_2\\iff W= W_{t2}\\iff W= \\frac{1}{2}mv_2^2$<\/span>  $\\Rightarrow 6500= \\frac{1}{2}.65.v_2^2 \\Rightarrow v_2= 10\\sqrt{2}= 14,14(m\/s)$<\/span> \u0110áp án \u0111úng: A. 10 m\/s; 14,14 m\/s.<\/strong><\/span><\/p>","type":"choose","extra_type":"classic","user_id":"149","test":"0","date":"2023-03-30 13:36:11","option_type":"txt","len":2}]}