Lực đẩy Archimedes

Home Lớp 8 Khoa học tự nhiên 8 - sách Kết nối tri thức Bài 17: Lực đẩy ArchimedesBài tập cơ bản

{"common":{"save":0,"post_id":"8636","level":1,"total":10,"point":10,"point_extra":0},"segment":[{"id":"9016","post_id":"8636","mon_id":"1159539","chapter_id":"1159710","question":"L\u1ef1c \u0111\u1ea9y Archimedes ph\u1ee5 thu\u1ed9c vào y\u1ebfu t\u1ed1 nào?<\/p>","options":["A.<\/strong> Kh\u1ed1i l\u01b0\u1ee3ng c\u1ee7a v\u1eadt.<\/p>","B.<\/strong> Tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a ch\u1ea5t l\u1ecfng.<\/p>","C.<\/strong> Th\u1ec3 tích c\u1ee7a v\u1eadt n\u1eb1m trên m\u1eb7t n\u01b0\u1edbc.<\/p>","D.<\/strong> Nhi\u1ec7t \u0111\u1ed9 c\u1ee7a ch\u1ea5t l\u1ecfng.<\/p>"],"correct":"2","level":"1","hint":"L\u1ef1c \u0111\u1ea9y Archimedes ph\u1ee5 thu\u1ed9c vào tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a ch\u1ea5t l\u1ecfng và th\u1ec3 tích ph\u1ea7n v\u1eadt chìm trong ch\u1ea5t l\u1ecfng.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> B. Tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a ch\u1ea5t l\u1ecfng.<\/p>Gi\u1ea3i thích:<\/em><\/p>Theo công th\u1ee9c l\u1ef1c \u0111\u1ea9y Archimedes: $F_A=d.V$<\/span> , trong \u0111ó $d$<\/span> là tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a ch\u1ea5t l\u1ecfng và $V$<\/span> là th\u1ec3 tích ph\u1ea7n v\u1eadt chìm trong ch\u1ea5t l\u1ecfng.<\/p>Do \u0111ó, l\u1ef1c \u0111\u1ea9y Archimedes ph\u1ee5 thu\u1ed9c vào tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a ch\u1ea5t l\u1ecfng.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"132","test":"0","date":"2025-03-27 10:10:58","option_type":"txt","len":3},{"id":"9017","post_id":"8636","mon_id":"1159539","chapter_id":"1159710","question":"M\u1ed9t v\u1eadt chìm hoàn toàn trong n\u01b0\u1edbc thì l\u1ef1c \u0111\u1ea9y Archimedes có giá tr\u1ecb nh\u01b0 th\u1ebf nào so v\u1edbi tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt?<\/p>","options":["A.<\/strong> L\u1edbn h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt.<\/p>","B.<\/strong> Nh\u1ecf h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt.<\/p>","C.<\/strong> B\u1eb1ng tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt.<\/p>","D.<\/strong> Không xác \u0111\u1ecbnh \u0111\u01b0\u1ee3c.<\/p>"],"correct":"2","level":"1","hint":"Khi v\u1eadt chìm hoàn toàn, l\u1ef1c \u0111\u1ea9y Archimedes và tr\u1ecdng l\u01b0\u1ee3ng s\u1ebd có m\u1ed1i quan h\u1ec7 xác \u0111\u1ecbnh.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> B. Nh\u1ecf h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt.<\/p>Gi\u1ea3i thích:<\/em><\/p>N\u1ebfu v\u1eadt chìm hoàn toàn thì có th\u1ec3 x\u1ea3y ra hai tr\u01b0\u1eddng h\u1ee3p:<\/p>- N\u1ebfu v\u1eadt n\u1eb7ng h\u01a1n l\u1ef1c \u0111\u1ea9y Archimedes, nó s\u1ebd chìm xu\u1ed1ng \u0111áy.<\/p>- N\u1ebfu l\u1ef1c \u0111\u1ea9y Archimedes b\u1eb1ng tr\u1ecdng l\u01b0\u1ee3ng v\u1eadt, nó s\u1ebd l\u01a1 l\u1eedng trong n\u01b0\u1edbc. Do \u0111ó, trong \u0111a s\u1ed1 tr\u01b0\u1eddng h\u1ee3p, l\u1ef1c \u0111\u1ea9y Archimedes nh\u1ecf h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt khi v\u1eadt chìm hoàn toàn.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"132","test":"0","date":"2025-03-27 17:00:17","option_type":"txt","len":2},{"id":"9131","post_id":"8636","mon_id":"1159539","chapter_id":"1159710","question":"Khi th\u1ea3 m\u1ed9t v\u1eadt vào n\u01b0\u1edbc, làm sao \u0111\u1ec3 bi\u1ebft v\u1eadt \u0111ó có n\u1ed5i hay không?<\/p>","options":["A.<\/strong> So sánh kh\u1ed1i l\u01b0\u1ee3ng riêng c\u1ee7a v\u1eadt v\u1edbi kh\u1ed1i l\u01b0\u1ee3ng riêng c\u1ee7a n\u01b0\u1edbc.<\/p>","B.<\/strong> So sánh th\u1ec3 tích c\u1ee7a v\u1eadt v\u1edbi th\u1ec3 tích c\u1ee7a n\u01b0\u1edbc.<\/p>","C.<\/strong> So sánh nhi\u1ec7t \u0111\u1ed9 c\u1ee7a v\u1eadt v\u1edbi nhi\u1ec7t \u0111\u1ed9 c\u1ee7a n\u01b0\u1edbc.<\/p>","D.<\/strong> So sánh tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a v\u1eadt v\u1edbi tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a n\u01b0\u1edbc.<\/p>"],"correct":"4","level":"1","hint":"V\u1eadt n\u1ed5i hay chìm ph\u1ee5 thu\u1ed9c vào s\u1ef1 chênh l\u1ec7ch tr\u1ecdng l\u01b0\u1ee3ng riêng gi\u1eefa v\u1eadt và n\u01b0\u1edbc.<\/p>","answer":"\u0110áp án \u0111úng là:<\/strong> D. So sánh tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a v\u1eadt v\u1edbi tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a n\u01b0\u1edbc.<\/p>Gi\u1ea3i thích:<\/em><\/p>N\u1ebfu tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a v\u1eadt nh\u1ecf h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a n\u01b0\u1edbc thì v\u1eadt s\u1ebd n\u1ed5i. N\u1ebfu tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a v\u1eadt l\u1edbn h\u01a1n tr\u1ecdng l\u01b0\u1ee3ng riêng c\u1ee7a n\u01b0\u1edbc thì v\u1eadt s\u1ebd chìm.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"132","test":"0","date":"2025-03-30 21:40:30","option_type":"txt","len":3}]}