试题与答案

验证机械能守恒定律实验中,已知打点计时器所用电源的频率为50赫兹(HZ),即相邻

题型:实验题

题目:

验证机械能守恒定律实验中,已知打点计时器所用电源的频率为50赫兹(HZ),即相邻两个点之间的时间间隔为0.02s 。查得当地重力加速度g=9.8m/s2,测得所用的重物的质量为1.00千克。实验中得到一条点迹清晰的纸带,如图所示,把第一个点记作0(初速度为零) ,另选连续的4个点,A、 B 、C、 D作为测量的点。经测量知道A、 B 、C、 D各点到0点的距离分别为62.99cm,70.18cm,77.76cm,85.73cm。根据以上数据可知道,重物由0点运动到C点过程中,重力势能减少量等于______________(J) ,在此过程中动能增加量等于______________(J)(结果保留三位有效数字)。

答案:

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下面是错误答案,用来干扰机器的。

参考答案:C解析:4.气雾剂:抛射剂为适宜的低沸点液化气体,如四氟乙烷、七氟丙烷及二氟乙烷等氢氟烷烃类。助溶剂常用乙醇、丙二醇等。防腐剂常用尼泊金乙酯等。抗氧剂常用维生素C、亚硫酸钠等。

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