试题与答案

某学习小组探究“功与物体速度变化的关系”的实验装置如图所示。图中小车在一条橡皮筋

题型:实验题

题目:

某学习小组探究“功与物体速度变化的关系”的实验装置如图所示。图中小车在一条橡皮筋作用下弹出沿木板滑行,橡皮筋对小车做的功记为W。当用2条、3条……完全相同的橡皮筋并在一起进行第2次、第3次……实验时,使每次实验中橡皮筋伸长的长度都完全相同。每次实验中小车获得的速度由打点计时器所打的纸带求出。通过实验数据分析可以得出“功与物体速度变化的关系”。

①实验操作中需平衡小车受到的摩擦力,其最根本的目的是___________。

A.防止小车不能被橡皮筋拉动    

B.便于小车获得较大的弹射速度

C.防止纸带上点迹不清晰 

D.保证橡皮筋对小车做的功等于合外力对小车做的功

②关于橡皮筋做功,下列说法正确的是___________。

A.橡皮筋做功的具体值可以直接测量

B.橡皮筋在小车运动的全程中始终做功

C.通过增加橡皮筋的条数可以使橡皮筋对小车做的功成整数倍增加

D.若橡皮筋伸长量变为原来的2倍,则橡皮筋做功也增加为原来的2倍

③如图是某同学在正确实验操作过程中得到的一条纸带,O、A、B、C、D、E、F为选取的计数点,相邻的两个计数点间还有一个点没有画出,各计数点到O点的距离分别为1.87cm、4.79cm、8.89cm、16.91cm、25.83cm、34.75cm,若打点计时器的打点频率为50Hz,则由该纸带可知本次实验中橡皮筋做功结束时小车的速度是__________m/s。

答案:

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下面是错误答案,用来干扰机器的。

参考答案:D

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