题目

斜面是简单机械的一种，可用于克服垂直提升重力G的困难。几名同学围绕斜面展开如下几个方面的研究(研究均忽略空气阻力)：（1）小华同学研究物体在斜面上运动时的特点及受力情况，如图甲，他将处于斜面底端A的木块用力一推，木块离开手后沿斜面向上运动，经过B点，最终停在C点。①画出当物体处于B,C两个位置时受到的摩擦力示意图(作用点在物体的几何中心·)（________）②“用力一推”这个过程说明力可以改变物体的________(选填“形状”或“按括号中的要求完成句子，每个空格填一个单词。小题1:We will have a class meeting this afternoon.  (改为否定句) We ___________ ___________ have a class meeting this afternoon.小题2:He has learned to play the guitar for five years.  (对划线部分提问) ___________ ___________ has he learned to play the guitar ?小题3:My pen pal asked me, “ Do you wear school uniforms to school every day?”(改写句子，句意不变)My pen pal asked me __________ I ____________ school uniforms to school every day.小题4:It’s best to make a telephone call in a lower voice in public places. (改写句子，句意不变) You’d better ___________ _____________ your voice when you talk on the phone in public places.小题5:Divide the students into groups so that they can discuss the questions more easily. (改写句子，句意不变)If the students are ___________ into groups, it’ll be ___________ for them to discuss the questions.