-
题目： 单选
物块重G=20N，用P=40N的力按图示方向把物块压在铅直墙上，物块与墙之间的摩擦系数，f=
／4，则作用在物块上的摩擦力等于（）
答案不对？请尝试站内搜索
推荐知识点:
- 每个风帽上的三个小孔呈（）分布。
- 动力性梗阻致急性尿潴留的病因是（）
- 鼻咽癌原发病灶的典型PET/CT征象是（）
- 市场初步调查或对市场情况不甚明了多采了（）。
- 红花抑制血小板聚集的有效成分是（）
- Research Is a State of Mind For many years there has been much misunderstanding as to just what research is. The popular conception seems to be that there is something mysterious about it， and before any research can be done it is necessary to have expensive scientific apparatus and large， elaborately equipped laboratories. Actually， this is not so. （6） It is a simple， organized way of trying to accomplish something you wish to do—so simple that anyone can do research anywhere at any time. First， you select the problem you would like to solve， then you list at least ten reasons why it has not been solved. （7） It takes just as much effort to solve a useless problem as a useful one. （8） After carefully—and I want to emphasize that word “carefully”—selecting the problem and the ten things between you and the solution， you then use the same procedure as in solving a crossword puzzle.（9）In the solution of the remaining obstacles you may need some simple apparatus， but the things you will probably need most are infinite patience and persistence. Few people realize the difficulties of doing any new thing. Maybe one of the reasons people are so easily discouraged is because of their education. During all our years at school we were examined two or three times a year. If we failed once， we were out. （10）If we are going to make progress， we must learn to fail intelligently so that we won't become discouraged at the 99.9 per cent failure. 6.（） 7.（） 8.（） 9.（） 10.（）
- 在申请入台证时，财力证明包括有：银行信用卡必须为（）级别以上
- 简述我国农业劳动力的特点。
- 我国心理咨询已经具备了职业化的基本条件。这样的估计，可以由六种可操作性指标予以标定。下列哪项不是可操作性指标?()
- 患儿，女性，6岁，右下第一磨牙已经完整萌出，窝沟较深，医生决定对该牙进行封闭，在清洁牙面、采用含磷酸的凝胶酸蚀，酸蚀时间为（）