九年级轻松快乐过寒假答案.doc

物理练习1 在力的方向上移动的距离 静止 F1*L1=F2*L2 J 50 做功快慢 单位时间内做功的多少 P=W/t 400 0 动滑轮 定滑轮 滑轮组 B B 省 A 500 变小 不变 CCAAB 66.7% 74.1% 在动滑轮重不变的情况下，物体越重，机械效率越高 G总=Fn=15*2=30N G=G总-G动=30-5=25N η=G/G总*100%=25/30*100%≈83.3% 过程好烦啊不写了 360N 36W 练习二 水的比热容大 对外做功 做功 机械 内 速度 物体被举高高度 动能 动 重力势 2.1*10^6 减少 做功 转动 3：2 2：3 100 热值高 燃烧无污染 水蒸气 活塞 降低 减小 内 机械能 CCACC 14略 1.26*10^5J 1400J/S 7L 1.008*10^7J 6*10^7J 16.8% 煤不完全燃烧 放出的热量没有被水完全吸收 练习三 串联 并联 串联 并联 并 串联 并 L2,L3 串 L1,L2 并 2.5V 1.5V 短 L1 短路 b 3V 1.5V BBBBB 14，15略 练习四 小于 增大 20欧 20欧 16欧 5 60 温度 2.7 英语练习一 worry about be divided into worry too much keep secrets fargue with sb. forgive sb. for sth. show off give up easily take care of pay attention to different kinds of ideas devote to charity modest generous unlucky shy hard-working inpatient impossible unfair inactive full dishonest incorrect weak stupid to save not meeting to eat explaining putting butterfiles planning unfair leader energetic What is he like What does Sam often dream about Which women is our new teacher The were divided into 4 groups by Mr zhang His young sister is taken care of by Peter Your star sign is divided by your birthday His mother is so kind that shi helps others There is nothing wrong with Jims mind He is clever enough to solve the problem Can you tell me how to get to the nearest shop AAABB ADBAD AC CBCDA DABCD CACCCAB 作文略 英语练习二 prefer would rather would rather prefer would rather would rather prefer prefer prefer nothing noting everybody nobody anything nothing none anyone everyone something everybody BABDA CBCBB I prefer watching TV to go to have a walk with you Its interesting to chat with others If you fell sad or scared,try to wear in y