问题
选择题
| 如图所示，AB是一质量为m的均匀细直杆，A端靠在光滑的竖直墙壁上，B端置于水平地面上，杆身与竖直方向夹角为θ，杆与地面的摩擦系数为μ，保持平衡，则此时杆与地面的摩擦力为（ ） A． B． C． D．μmg  |
mgtgθ
mgsinθ
答案
答案：A
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| 如图所示，AB是一质量为m的均匀细直杆，A端靠在光滑的竖直墙壁上，B端置于水平地面上，杆身与竖直方向夹角为θ，杆与地面的摩擦系数为μ，保持平衡，则此时杆与地面的摩擦力为（ ） A． B． C． D．μmg |
答案：A
Maybe you are an average student. You probably think you will never be a top student. This is not necessary so, however. Anyone can become a better student if he or she wants to. Here’s how. 1) Plan your time carefully. When you plan your week, you should make a list of things that you have to do. After making this list, you should make a schedule of your time. First your time for eating, sleeping, dressing, etc. then decide a good, regular time for studying. Don't forget to set aside enough time for entertainment. A weekly schedule may not solve all your problems, but it will force you to realize what is happening to your time. 2) Find a good place to study. Look around the house for a good study area. Keep this space, which may be a desk or simply a corner of your room, free of everything but study materials. No games, radios, or television! When you sit down to study, concentrate on the subject. 3) Make good use of your time in class. Take advantage of class time to listen to everything the teachers say. Really listening in class means less work later. Taking notes will help you remember what the teacher says. 4) Study regularly. When you get home from school, go over your notes. Review the important points that your teacher mentioned in class. If you know what your teacher is going to discuss the next day, read that material will become more meaningful, and you will remember it longer. 5) Develop a good attitude about tests. The purpose of a test is to show what you have learned about a subject. They help you remember your new knowledge. The world won’t end if you don't pass a test, so don't be overly worried. There are other methods that might help you with your studying. You will probably discover many others after you have tried these. Title: How to become a better student
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