题目

阅读理解 Vera is thirteen years old. She was born onJuly 27th. Mrs. Smith is her mother. Today is Vera's birthday. There is a partyfor her, Lots of her friends come to her birthday party. A birthday cake is onthe table. There are some bananas, oranges, strawberries and apples on thetable, too. But Vera doesn't like them. What does she want? Can you guess? Just then Vera sees a red card in hermother's hand. It says, Happy birthday to you, dear(亲爱的) Vera. There is a nice present for you. Open the box on yourdresser, you can find it. Vera runs to her dresser and opens the box.Ah, a nice在探究“滑动摩擦力的大小与什么有关”的实验中，所用装置如图所示．(1) 从弹簧测力计直接读出的是对木块的拉力大小，实验中需要让拉力与木块所受的滑动摩擦力大小相等，则应满足的主要条件是：木块放在水平面上，拉动木块时，木块应处于__运动状态：拉力方向水平．(2) 拉动木块前，应将测力计沿______方向放置，然后进行调零．(3) 利用如图所示的装置进行相关试验后，在木块上再叠加另一个木块来进行实验．分析叠放木块与不叠放木块两种情况对应的数据，是为了验证下列猜想中的______．A. 滑动摩擦力的大小与压力的大小有关 B．滑动摩擦力的大小与接触面的粗糙程度有关C. 滑动摩擦力的大小与接触面积大小有关 D、滑动摩擦力的大小与运动的速度大小有关(4) 交流评估时，某实验小组提出：实验过程中，弹簧测力计的示数不容易稳定．可能的原因是__．A. 木板的长度太长 B．木板的粗糙程度不均匀C. 弹簧测力计的分度值太大 D．木块与木板的接触面积太大．