Sự rơi tự do - Bài tập nâng cao

Home Lớp 10 Vật lý 10 - Sách kết nối tri thức Bài 10: Sự rơi tự doBài tập nâng cao

{"common":{"save":0,"post_id":"6348","level":3,"total":11,"point":9,"point_extra":1},"segment":[{"id":"5926","mon_id":"1158790","chapter_id":"1158795","post_id":"6348","question":"Hai v\u1eadt \u0111\u01b0\u1ee3c th\u1ea3 r\u01a1i t\u1ef1 do \u0111\u1ed3ng th\u1eddi t\u1eeb hai \u0111\u1ed9 cao khác nhau $h_1$<\/span> va\u0300 $h_2$<\/span>. Kho\u1ea3ng th\u1eddi gian r\u01a1i c\u1ee7a v\u1eadt th\u1ee9 nh\u1ea5t l\u1edbn g\u1ea5p ba l\u1ea7n kho\u1ea3ng th\u1eddi gian r\u01a1i c\u1ee7a v\u1eadt th\u1ee9 hai. B\u1ecf qua l\u1ef1c c\u1ea3n c\u1ee7a không khí. T\u1ec9 s\u1ed1 các \u0111\u1ed9 cao là bao nhiêu?<\/p>","options":["A. ${h_1\\over h_2}=2$<\/span>","B. ${h_1\\over h_2}=9$<\/span>","C. ${h_1\\over h_2}=4$<\/span>","D. ${h_1\\over h_2}=3$<\/span>"],"correct":"2","level":"3","hint":"S\u1eed d\u1ee5ng công th\u1ee9c:  $t=\\sqrt{2h\\over g}$<\/span><\/p>","answer":"Ch\u1ecdn B.<\/strong><\/span> Ta có:  $t_1=3t_2 \\Rightarrow\\sqrt{2h_1\\over g}=3.\\sqrt{2h_2\\over g} \\Rightarrow \\sqrt{h_1\\over h_2}=3 \\Rightarrow {h_1\\over h_2}=9$<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2022-10-27 03:46:27","option_type":"math","len":0},{"id":"5927","mon_id":"1158790","chapter_id":"1158795","post_id":"6348","question":"N\u1ebfu l\u1ea5y gia t\u1ed1c r\u01a1i t\u1ef1 do là g = 10 $m\/s^2$<\/span> thì t\u1ed1c \u0111\u1ed9 trung bình c\u1ee7a m\u1ed9t v\u1eadt trong chuy\u1ec3n \u0111\u1ed9ng r\u01a1i t\u1ef1 do không v\u1eadn t\u1ed1c ban \u0111\u1ea7u, t\u1eeb \u0111\u1ed9 cao 45m xu\u1ed1ng t\u1edbi \u0111\u1ea5t s\u1ebd là<\/p>","options":["A. 15 m\/s","B. 8 m\/s","C. 10 m\/s","D. 1 m\/s"],"correct":"1","level":"3","hint":"S\u1eed d\u1ee5ng công th\u1ee9c:  $\\nu_{tb}={d\\over t}$<\/span> và $t=\\sqrt{2h\\over g}$<\/span>  \u0111\u1ec3 gi\u1ea3i.<\/p>","answer":"Ch\u1ecdn A.<\/strong><\/span> Ta có:  $\\nu_{tb}={d\\over t}={h\\over\\sqrt{2h\\over g}}={45\\over\\sqrt{2.45\\over 10}}=15(m\/s)$<\/span><\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2022-10-27 03:50:46","option_type":"txt","len":0},{"id":"5928","mon_id":"1158790","chapter_id":"1158795","post_id":"6348","question":"\u1ede cùng \u0111\u1ed9 cao v\u1edbi v\u1eadt A ng\u01b0\u1eddi ta th\u1ea3 v\u1eadt B r\u01a1i sau v\u1eadt A m\u1ed9t th\u1eddi gian 0,1 s. H\u1ecfi sau bao lâu k\u1ec3 t\u1eeb lúc th\u1ea3 v\u1eadt A thì kho\u1ea3ng cách gi\u1eefa chúng là 1 m? Bi\u1ebft g = 10 $m\/s^2$<\/span>.<\/p>","options":["A. 7,5 s","B. 8,5 s","C. 9,5 s","D. 1,05 s"],"correct":"4","level":"3","hint":"Vi\u1ebft ph\u01b0\u01a1ng trình \u0111\u1ed9 d\u1ecbch chuy\u1ec3n c\u1ee7a 2 v\u1eadt. 2 v\u1eadt cách nhau 1 m  $\\Rightarrow \\left[\\begin{array}{c}d_A-d_B=1\\\\d_B-d_A=1\\end{array}\\right.$<\/span> Gi\u1ea3i 2 ph\u01b0\u01a1ng trình trên \u0111\u1ec3 tr\u1ea3 l\u1eddi câu h\u1ecfi.<\/p>","answer":"Ch\u1ecdn D.<\/strong><\/span> Ch\u1ecdn tr\u1ee5c Ox có ph\u01b0\u01a1ng th\u1eb3ng \u0111\u1ee9ng, chi\u1ec1u d\u01b0\u01a1ng h\u01b0\u1edbng t\u1eeb trên xu\u1ed1ng, g\u1ed1c t\u1ecda \u0111\u1ed9 t\u1ea1i v\u1ecb trí th\u1ea3 2 v\u1eadt, g\u1ed1c th\u1eddi gian là lúc th\u1ea3 v\u1eadt A. Ph\u01b0\u01a1ng trình \u0111\u1ed9 d\u1ecbch chuy\u1ec3n c\u1ee7a v\u1eadt A:  $d_A={1\\over2}gt^2$<\/span> Ph\u01b0\u01a1ng trình \u0111\u1ed9 d\u1ecbch chuy\u1ec3n c\u1ee7a v\u1eadt B:  $d_b={1\\over2}g(t-0,1)^2$<\/span> 2 v\u1eadt cách nhau 1 m  $\\Rightarrow \\left[\\begin{array}{c}d_A-d_B=1\\\\d_B-d_A=1\\end{array}\\right.\\Rightarrow \\left[\\begin{array}{c}{1\\over2}gt^2-{1\\over2}g(t-0,1)^2=1\\\\{1\\over2}g(t-0,1)^2-{1\\over2}gt^2=1\\end{array}\\right.\\Rightarrow \\left[\\begin{array}{c}t=1,05\\\\t=-0,95\\end{array}\\right.$<\/span> Lo\u1ea1i nghi\u1ec7m t = -0,95 vì t > 0, nh\u1eadn nghi\u1ec7m t = 1,05 V\u1eady sau 1,05 s k\u1ec3 t\u1eeb khi th\u1ea3 v\u1eadt A, 2 v\u1eadt cách nhau 1 m.<\/p>","type":"choose","extra_type":"classic","user_id":"147","test":"0","date":"2022-10-27 04:41:03","option_type":"txt","len":0}]}