Động năng. Thế năng (trung bình)

Home Lớp 9 Khoa học tự nhiên 9 - sách kết nối tri thức Bài 2: Động năng. Thế năngBài tập trung bình

{"common":{"save":0,"post_id":"8250","level":2,"total":10,"point":10,"point_extra":0},"segment":[{"id":"9485","post_id":"8250","mon_id":"1159533","chapter_id":"1159535","question":"Khi m\u1ed9t v\u1eadt \u0111\u01b0\u1ee3c nâng lên \u0111\u1ed9 cao $h$<\/span>, n\u0103ng l\u01b0\u1ee3ng c\u1ee7a v\u1eadt thay \u0111\u1ed5i nh\u01b0 th\u1ebf nào?<\/p>","options":["A. Th\u1ebf n\u0103ng t\u0103ng, \u0111\u1ed9ng n\u0103ng không \u0111\u1ed5i.","B. Th\u1ebf n\u0103ng t\u0103ng, \u0111\u1ed9ng n\u0103ng gi\u1ea3m.","C. Th\u1ebf n\u0103ng không \u0111\u1ed5i, \u0111\u1ed9ng n\u0103ng gi\u1ea3m.","D. C\u1ea3 th\u1ebf n\u0103ng và \u0111\u1ed9ng n\u0103ng \u0111\u1ec1u t\u0103ng."],"correct":"2","level":"2","hint":"","answer":"\u0110áp án: B. Th\u1ebf n\u0103ng t\u0103ng, \u0111\u1ed9ng n\u0103ng gi\u1ea3m. Gi\u1ea3i thích: Khi v\u1eadt \u0111\u01b0\u1ee3c nâng lên, \u0111\u1ed9 cao t\u0103ng làm th\u1ebf n\u0103ng t\u0103ng ($W_t = mgh$<\/span>), \u0111\u1ed3ng th\u1eddi v\u1eadn t\u1ed1c gi\u1ea3m làm \u0111\u1ed9ng n\u0103ng gi\u1ea3m.  <\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 13:42:28","option_type":"txt","len":2},{"id":"9486","post_id":"8250","mon_id":"1159533","chapter_id":"1159535","question":"Khi m\u1ed9t qu\u1ea3 bóng \u0111\u01b0\u1ee3c th\u1ea3 r\u01a1i t\u1eeb \u0111\u1ed9 cao $h$<\/span>, t\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1m \u0111\u1ea5t, n\u0103ng l\u01b0\u1ee3ng nào c\u1ee7a qu\u1ea3 bóng là l\u1edbn nh\u1ea5t?<\/p>","options":["A. Th\u1ebf n\u0103ng h\u1ea5p d\u1eabn.","B. \u0110\u1ed9ng n\u0103ng.","C. Th\u1ebf n\u0103ng \u0111àn h\u1ed3i.","D. C\u01a1 n\u0103ng."],"correct":"2","level":"2","hint":"","answer":"\u0110áp án: B. \u0110\u1ed9ng n\u0103ng. Gi\u1ea3i thích: T\u1ea1i th\u1eddi \u0111i\u1ec3m ch\u1ea1m \u0111\u1ea5t, v\u1eadn t\u1ed1c c\u1ee7a qu\u1ea3 bóng \u0111\u1ea1t giá tr\u1ecb l\u1edbn nh\u1ea5t, nên \u0111\u1ed9ng n\u0103ng \u0111\u1ea1t giá tr\u1ecb l\u1edbn nh\u1ea5t.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 13:44:31","option_type":"txt","len":2},{"id":"9487","post_id":"8250","mon_id":"1159533","chapter_id":"1159535","question":"Trong m\u1ed9t h\u1ec7 kín, khi không có l\u1ef1c nào khác ngoài l\u1ef1c h\u1ea5p d\u1eabn tác d\u1ee5ng lên v\u1eadt, c\u01a1 n\u0103ng c\u1ee7a v\u1eadt:<\/p>","options":["A. T\u0103ng d\u1ea7n theo th\u1eddi gian.","B. Gi\u1ea3m d\u1ea7n theo th\u1eddi gian.","C. Không \u0111\u1ed5i theo th\u1eddi gian.","D. Bi\u1ebfn \u0111\u1ed5i tùy thu\u1ed9c vào \u0111\u1ed9ng n\u0103ng."],"correct":"3","level":"2","hint":"","answer":"\u0110áp án: C. Không \u0111\u1ed5i theo th\u1eddi gian. Gi\u1ea3i thích: Trong m\u1ed9t h\u1ec7 kín, khi ch\u1ec9 có l\u1ef1c h\u1ea5p d\u1eabn tác d\u1ee5ng, c\u01a1 n\u0103ng ($W = W_\u0111 + W_t$<\/span> ) \u0111\u01b0\u1ee3c b\u1ea3o toàn, không \u0111\u1ed5i theo th\u1eddi gian.<\/p>","type":"choose","extra_type":"classic","time":"0","user_id":"125","test":"0","date":"2024-12-31 15:45:21","option_type":"txt","len":2}]}