问题 单项选择题

如图,一质量为M的质量分布不均匀的多边形板AOB,边OA⊥OB且OA=OB=L,O点为水平固定转动轴,现用一水平拉力拉住A点,维持三角板处于OA竖直的静止状态,拉力大小为F,重力加速度为g,则三角板重心到AO的距离为()

A.

B.

C.

D.

答案

参考答案:A

解析:

由力矩平衡条件,FL=Mgx可得三角板重心到AO的距离为x=,选项A正确

单项选择题
单项选择题

At some time in your life you may have a p desire to do something strange or terrible. However, chances are that you don’t act on your impulse, but let it pass instead. You know that to commit the action is wrong in some way and that other people will not accept your behavior.
Perhaps the most interesting thing about the phenomenon of the behavior is how it can change over the years within the same society, how certain behavior and attitudes once considered taboo can become perfectly acceptable and natural at another point in time. Topics such as death, for example, were once considered so upsetting and unpleasant that it was a taboo to even tall about them. Now with the publication of important books such as "On Death and Dying" and "Learning to Say Goodbye", people have become more aware of the importance of expressing feelings about death and, as a result, are more willing to talk about this taboo subject.
One of the newest taboos in American society is the topic of fat. Unlike many other taboos, fat is a topic that Americans tall about constantly. It’s not taboo to tall about fat; it’s taboo to be fat. The "thin" look is thin, not fat.
In the work world, most companies prefer youthful-looking, trim executives to sell their image as well as their products to the public. The thin look is associated with youth, vigor and success. The fat person, on the other hand, is thought of as lazy and lacking in energy, self- respect. After all, people think, how can people who care about themselves, and therefore the way they look, permit themselves to become fat In an image-conscious society like the U.S., thin is "in", fat is "out".

In the U.S., the expression that thin is "in" and fat is "out" probably means ______.

A. thin is "diligent" and fat is "lazy"
B. thin is "fashionable" and fat is "unfashionable"
C. thin is "inside" and fat is "outside"
D. thin is "spiritless" and fat is "vigorous\