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问题 多选题

如图，把一石块从山崖上的A点向斜上方抛出，不计空气阻力，石块在B点落地时速度的大小与下列哪些物理量有关（　　）

A．石块的质量

B．石块抛出时的高度

C．石块抛出时初速度的大小

D．石块抛出时初速度与水平方向的夹角

答案

在整个过程中，有动能定理可知：mgh=

1
2
m
v22
-
1
2
m
v21

解得：v2=

v21
+2gh

所以v2只与h和v1有关，与其它量无关，

故选：BC．

问答题 简答题

重力勘探的先决条件、有利条件。什么是重力的正反演。
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问答题

Traditionally, the woman has held a low position in marriage partnerships. While her husband went his way, she had to wash, stitch and sew. Today the move is to liberate the woman, which may in the end strengthen the marriage union. Perhaps the greatest obstacle to friendship in marriage is the amount a couple usually sees of each other. Friendship in its usual sense is not tested by the strain of daily, year-long cohabitation. (46) Couples need to take up separate interests (and friendship) as well as mutually shared ones, if they are not to get used to the more attractive elements of each other’s personalities.
(47) Married couples are likely to exert themselves for guests--being amusing, discussing with passion and point--and then to fall into dull exhausted silence when the guests have gone. As in all friendship, a husband and wife must try to interest each other, and to spend sufficient time sharing absorbing activities to give-them continuing common interests, (48) But at the same time they must spend enough time on separate interests with separate people to preserve and develop their separate personalities and keep their relationship fresh.
(49) For too many highly intelligent working women, home represents chore obligations, because the husband only tolerates her work and does not participate in household chores. For too many highly intelligent working men, home represents dullness and complaints--from an over-dependent wife who will not gather courage to make their own life.
In such an atmosphere, the partners grow further and further apart, both love and liking disappearing. (50) For too many couples with children, the children are allowed to command all time and attention, allowing the couple no time to develop liking and friendship, as well as love, allotting exclusive parental roles.
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