问题
填空题
如图所示，小车后壁上附有一块质量为m的物块，它与车壁间的动摩擦因数为μ。当小车向左加速运动，其加速度至少为______时，物块可恰好不落下来（设最大静摩擦力与滑动摩擦力大小相等）。若小车向左加速度再增大，物块相对于小车静止，物块所受到的摩擦力将______（增大、减少或不变）。
答案
g/μ；不变
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如图所示，小车后壁上附有一块质量为m的物块，它与车壁间的动摩擦因数为μ。当小车向左加速运动，其加速度至少为______时，物块可恰好不落下来（设最大静摩擦力与滑动摩擦力大小相等）。若小车向左加速度再增大，物块相对于小车静止，物块所受到的摩擦力将______（增大、减少或不变）。
g/μ；不变
| Many researchers have found greater dependence and obedience in very young girls, greater autonomy and activity in boys. When a barrier is set up to separate children from their mothers, boys try to knock it down; girls cry helplessly. There is little doubt that mother’s encouragement or discouragement—of such behavior plays a major role in determining adult personality. For example, a mother often stimulates male autonomy by throwing a toy far away from her young son, thus silently suggesting to him that he leaves her to get it. Animal studies suggest that there may be a biological factor in material behavior; mothers of some monkeys punish their male babies earlier and more often than their female offspring; they also touch their female babies more often and act more protectively toward them. As for the controversial question of female "passivity", psychologist Helen Deutsh believes that the concept has been misunderstood. "There is no contradiction between being feminine and working. The self can be active in both men and women," she says. It is only in love and sex that passivity is particularly appropriate for women. As she sees it, passivity is no more than a king of openness and warmth; it does not mean "inactivity of emptiness". Another controversy ranges over the effect of hormones. Aggressive women; who discount hormonal influence, disagree violently with scientific researchers, who almost unanimously agree that hormones help determine how people feel and act. So far, there have been few studies of male hormones, but scientists think they may eventually discover hormonal cycles in men that produce cyclic changes in mood and behavior. As for females, studies have indicated that 49 percent of female medical and surgical admissions, most psychiatric hospital admission and 62 percent of violent crimes among women prisoners are related with hormonal cycles in women. |
What is the best title for this passage
A．Hormone Effect
B．Male and Female
C．Passivity and Activity
D．Female Passivity