题干

如图所示,小车上有一定滑轮,跨过定滑轮的绳上一端系一重球,另一端系在弹簧秤上,弹簧秤固定在小车上.开始时小车处在静止状态.当小车匀加速向右运动时(    )

A:弹簧秤读数及小车对地面压力均增大

B:弹簧秤读数及小车对地面压力均变小

C:弹簧秤读数变大,小车对地面的压力不变

D:弹簧秤读数不变,小车对地面的压力变大

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答案(点此获取答案解析)

C

同类题2

Values join us together and set us apart. Today, our society has a terrible lack(缺乏)of values. Here are some social values that everyone needs.
◆Respect
Respect means to respect(尊重)others in everyday life. Even if you are against a person, it is important to have respect. It is this respect that makes us human. Without this respect, we become  animals. We need to respect our friends for our friendships. We even need to respect our enemies, because they help us to grow up and be stronger. Respect is one of the crucial values in a relationship.
◆Love
Love is everything. With love in our hearts, we feel no need to hurt another. With love in our hearts, we will pay more attention to the similarities in opinions rather than the disagreement. If we want others to be good to us, we need to be good to them. After all, we give love to get love, right?
◆Loyalty
People often forget the meaning and importance of loyalty(忠诚). Loyalty is necessary for people to believe in each other. In no matter what kind of relationship, we need to believe in each other so that we can work together towards the same goal.
◆Honesty
Honesty is to show other people who we really are. Honesty helps us do better, because it makes us realize our problems and find ways to solve them. It is this honesty, that will make others help you out, not because you need it. But, because they have problems too, which you can help out with. This honesty will help us follow the other values in society and, truly, "heal the world"!