图所示是“研究滑动摩擦力的大小与哪些因素有关的实验．(1)在实验中.用弹簧测力计拉着木块时.应水平地拉动.且使它在固定的水平面上做运动．根据 ——青夏教育精英家教网——

（8分）图所示是“研究滑动摩擦力的大小与哪些因素有关”的实验．
（1）在实验中，用弹簧测力计拉着木块时，应水平地拉动，且使它在固定的水平面上做____________________运动．根据___________________条件可知，木块所受摩擦力的大小等于弹簧测力计的示数．

（2）将图（a）和图（b）的实验进行比较可知，滑动摩擦力的大小与_
有关．
（3）将图（a）和图（c）的实验进行比较可知，滑动摩擦力的大小与有关．

（8分）用一个动滑轮把重480N的砖块拉到距地面10m高的楼上，所用的拉力为300N，试求有用功，总功和滑轮的机械效率各是多少?

What am I doing with my daughter at home? Rather than read aloud from books, we
go to dinner and have a very good time. This is usually when her Mom isn't around, and this is when my little girl and I relate better. They're alone together so much. We're seldom alone. When we're alone together, she and I somehow behave differently. We learn about each other. She learns that I'm her father. I learn that she's my daughter. It's a strange feeling, but any parent knows what I'm talking about when I say that I often look at my daughter and wonder just whose kid she is. Where'd she suddenly come from? And why on earth did she pick Laura and me for parents?
When my daughter and I are alone she'll hold my hand and say, “I just love you so much, Daddy!” She's so used to my leaving that when I tell her she and I are going to hang out all night, she gets this great look on her face and says, “We've got so much to do, Dad!” There's nothing like it in the world.
I want my relationship with my daughter to keep growing, so I've been giving my wife a couple of hundred dollars each week and making her go to the shopping center with her girlfriends, or something—anything!
But this closeness is not without its problems. When I'm sitting there playing with her Barbie doll(巴比娃娃)， washing her hair, a voice in me suddenly says, “I've got to get a drink and get out of here.” Right in the middle of all this pleasantness, the voice goes, “Look at yourself! You're washing dolls!”
1.Why does the husband give his wife so much money each week?
A. He wants her to buy more things for the family.
B. She can do whatever she likes with the money.
C. He can spend more time with his daughter.
D. She can spend more time with her friends.
2. Which of the following statements is true?
A. The father spends more time with the daughter than the mother does.
B.The daughter is happy when the father tells her he will be away.
C.The father is happy, hearing “We've got so much to do, Dad!”
D.The father is sure that the daughter is not his own.
3.What does the last paragraph tell us about the father?
A.He doesn't enjoy being with his daughter.
B.He doesn't like washing his daughter's hair.
C.He likes to enjoy himself by going out for a drink.
D.He has mixed feelings when he is with his daughter.

（8分）电给我们生活带来了极大的方便,但使用不当也会造成危险.小明家电能表的几个重要参数如图所示,家中铺设电路所用的电线允许通过的最大电流为15A,家中已有用电器的总功率为2200W,最近又准备购买一台功率为1500 W的电热水器,这种电热水器是否适合他家使用呢?小明对这个问题进行了认真的研究. （1）添置这么大功率的用电器，是否超过电能表的负荷？
(2)如果安装了这台电热水器,家中所有用电器同时工作时的最大电流将达到　　 A,家中电路所用的电线承受(选填“能”或“不能”).
（3）请你算一算：按照当地１ＫＷ·h电费为0.55元的标准，如果这台电热水器每天正常工作1 h，小明家一个月需多交纳多少电费？（每月按30天计算）

若四次测量一本书的宽度记录为：12.38cm，12.36cm，12.38cm，12.34cm，则这本书宽度平均值是( 　 )

B．12.365cm．

一条反射光线和镜面的夹角是30°，此时入射光线和反射光线的夹角是（）。

下列说法中正确的是（）

A．光在介质中总是沿直线传播的	B．光传播的速度是3×千米／秒
C．光在水中的传播速度小于在空气中的传播速度	D．“光年”是天文学中常用的时间单位

关于小孔成像, 下面说法中正确的是（）

A．小孔成的像一定比物体小	B．小孔成的像一定是虚像
C．小孔成的像是倒立的实像	D．小孔成的像是正立的实像

下列说法中错误的是（）

A．镜面反射、漫反射都遵从光的反射定律

B．法线就是垂直镜面的一条光线

C．折射角、反射角和入射角有时三者可能相等

D．隔着篝火的火焰观察对面的人，发现人的形状是扭曲的，这是由于光的传播发生了弯曲的结果

声音的产生和传播是有一定条件的，声的产生和声的接收都有一定的规律．在下面的说法中正确的是（）

A．有振动物体和传播振动的物体存在，一定可以听到声音

B．有声音，不一定有声源

C．听到声音时，是由于声源的移动造成的

D．在声音有传播物质存在的条件下，有振动物体，不一定产生可以听到的声音

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