问题
选择题
小明同学利用圆珠笔杆、钢丝、细绳制成了如图所示的滑轮组用其匀速提升重物,不考虑摩擦、笔杆和绳重,下列说法正确的是( ) A.拉细绳的力F等于钩码重力G的 B.拉细绳的力F等于钩码重力G的 C.拉细绳的力F等于钩码重力G的 D.拉细绳下降的距离是钩码上升高度的 ![]() |
答案
答案:C
小明同学利用圆珠笔杆、钢丝、细绳制成了如图所示的滑轮组用其匀速提升重物,不考虑摩擦、笔杆和绳重,下列说法正确的是( ) A.拉细绳的力F等于钩码重力G的 B.拉细绳的力F等于钩码重力G的 C.拉细绳的力F等于钩码重力G的 D.拉细绳下降的距离是钩码上升高度的 ![]() |
答案:C
阅读下列短文,从所给的四个选项中选出最佳答案. A young man once asked Albert Einstein, the great scientist, 1 the secret of success(成功) is. The scientist told him that the secret of success is 2 work. A few days later the young man asked him the same question again. Einstein was very 3 . He did not say 4 , but wrote 5 words on a piece of paper and handed it 6 the young man. The young man looked at the piece of paper. 7 it was written: A=X+Y+Z. “What does this mean?” asked the young man. “A means success,” explained the old scientist. “X stands for(代表) hard work, Y stands for good methods(方法), and Z…, Z means stopping 8 and getting down to work.”
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