题干

一根硬棒,在 ____能绕着固定点转动,这根硬棒就叫做杠杆;力臂是从 ____到力的 ____的距离.杠杆平衡条件表达式为:____;省力杠杆的l1____l2、费力杠杆的l1____l2、等臂杠杆的l1____l2
上一题 下一题 0.0难度 选择题 更新时间:2014-11-19 06:01:26

答案(点此获取答案解析)

力的作用下,支点,作用线,F1L1=F2L2,>,<,=

同类题3

        Some people think only school children do not agree with their parents, however, it is not true.   1  is a problem for parents and children of all ages. If it's hard for you to communicate with your   2 , don't worry about it. Here is some advice for you to bridge the generation gap (代沟).
        Don't argue with your parents. Don't get to your parents when you are   3 . Your parents probably won't   4your ideas if you are shouting at them. And you can't express yourself  5  if you are angry. Go someplace to cool off. Make sure you understand why you are unhappy. Then think about what you want to   6 to your parents. If you don't think you can speak to them at the moment,  7  writing a letter.
        Try to reach an agreement. Sometimes you and your parents  8  on something. You can keep your disagreement and try your best to   9 each other. Michael's mother didn't agree with him about buying a motorcycle. They  10  over it. But they finally came to an agreement. Michael bought the motorcycle, but only   11it on certain days.
      Of course, your parents might refuse to agree on something. In these  12 , it is especially   13to show love and respect to them. Showing respect will keep your relationship with your parents strong.
         Talk about your  14 . The values of your parents are probably different from those of your own. Tell your parents what you 15  about, and why. Understanding your values might help them see your purposes in life.
      A good relationship with your parents can make you a better and happier person. It is worth having a try!