{"common":{"save":0,"post_id":"8048","level":3,"total":10,"point":10,"point_extra":0},"segment":[{"id":"8923","post_id":"8048","mon_id":"1159533","chapter_id":"1159535","question":"<p>M\u1ed9t ô tô có kh\u1ed1i l\u01b0\u1ee3ng 1200kg t\u0103ng t\u1ed1c \u0111\u1ec1u t\u1eeb v\u1eadn t\u1ed1c 0 m\/s lên 10 m\/s trong 5 giây. Tính công su\u1ea5t trung bình c\u1ee7a \u0111\u1ed9ng c\u01a1 ô tô trong th\u1eddi gian này.<\/p>","options":["A. 12000 W","B. 24000 W","C. 6000 W","D. 36000 W"],"correct":"1","level":"3","hint":"","answer":"<p>\u0110áp án: B<\/p><p>L\u1eddi gi\u1ea3i:<\/p><p>\u0110\u1ed9ng n\u0103ng cu\u1ed1i c\u1ee7a ô tô là: <span class=\"math-tex\">$W = {1 \\over 2}mv^2$<\/span> = <span class=\"math-tex\">$ {1 \\over 2}$<\/span><span class=\"math-tex\">$.1200.10^2$<\/span> = <span class=\"math-tex\">$60000 J$<\/span><\/p><p>Công su\u1ea5t trung bình: <span class=\"math-tex\">$P = {A\\over t} $<\/span> = <span class=\"math-tex\">${60000\\over 5}$<\/span> = <span class=\"math-tex\">$12000 W$<\/span><\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-11-29 12:23:43","option_type":"txt","len":0},{"id":"8924","post_id":"8048","mon_id":"1159533","chapter_id":"1159535","question":"<p>M\u1ed9t ng\u01b0\u1eddi kéo m\u1ed9t v\u1eadt b\u1eb1ng l\u1ef1c 200 N trên \u0111o\u1ea1n \u0111\u01b0\u1eddng 5 m. Bi\u1ebft góc gi\u1eefa l\u1ef1c kéo và ph\u01b0\u01a1ng chuy\u1ec3n \u0111\u1ed9ng là 30°. Công mà ng\u01b0\u1eddi này th\u1ef1c hi\u1ec7n là:<\/p>","options":["A. 1000 J","B. 500 J","C. 866 J","D. 1500 J"],"correct":"1","level":"3","hint":"","answer":"<p>\u0110áp án: A <\/p><p>L\u1eddi gi\u1ea3i: <\/p><p>Công mà ng\u01b0\u1eddi này th\u1ef1c hi\u1ec7n là: <span class=\"math-tex\">$A = F.s.cos$<\/span> α = 200.5.cos 30° = 200.5.<span class=\"math-tex\">${ \\sqrt{3} \\over 2}$<\/span> = 1000 J<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-11-29 12:26:57","option_type":"txt","len":0},{"id":"8925","post_id":"8048","mon_id":"1159533","chapter_id":"1159535","question":"<p>M\u1ed9t ng\u01b0\u1eddi \u0111i xe \u0111\u1ea1p lên d\u1ed1c. Bi\u1ebft công su\u1ea5t c\u1ee7a ng\u01b0\u1eddi \u0111ó là 200 W, kh\u1ed1i l\u01b0\u1ee3ng xe và ng\u01b0\u1eddi là 70 kg, góc nghiêng c\u1ee7a d\u1ed1c là 30°, và <span class=\"math-tex\">$g=10 m\/s^2$<\/span>. T\u1ed1c \u0111\u1ed9 t\u1ed1i \u0111a mà ng\u01b0\u1eddi \u0111ó \u0111\u1ea1t \u0111\u01b0\u1ee3c khi lên d\u1ed1c là:<\/p>","options":["A. 1 m\/s","B. 2 m\/s","C. 0,5 m\/s","D. 3 m\/s"],"correct":"2","level":"3","hint":"","answer":"<p>\u0110áp án: B<\/p><p>L\u1eddi gi\u1ea3i:<\/p><p>- Công su\u1ea5t: <span class=\"math-tex\">$P = F.v$<\/span><\/p><p>v\u1edbi <span class=\"math-tex\">$F = m.g.sin$<\/span> α = 70.10.sin 30° = 70.10.0,5= 350 N<\/p><p>- T\u1ed1c \u0111\u1ed9 t\u1ed1i \u0111a mà ng\u01b0\u1eddi \u0111ó \u0111\u1ea1t \u0111\u01b0\u1ee3c khi lên d\u1ed1c là: <span class=\"math-tex\">$v = {P \\over F}$<\/span> <span class=\"math-tex\">$= {200\\over 350} $<\/span> ≈ 2 m\/s<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-11-29 12:33:51","option_type":"txt","len":0}]}
