海头高级中学2012-2013届高一下学期物理《第7章验证机械能守恒定律》教学课件.ppt

* 第九节　实验：验证机械能守恒定律学.科.网 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 目标导航 学习目标：1.掌握利用自由落体运动验证机械能守恒定律. 2.知道实验的原理、方法和过程. 3.会处理实验数据，并能对实验结果进行讨论及误差分析. 重点难点：实验条件的控制及数据处理. 学.科.网 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 新知初探·自主学习 一、实验原理 1.机械能守恒定律 (1)当只有重力做功时，物体的动能和重力势能发生相互转化，但机械能的总量保持不变． (2)做自由落体运动的物体，只受重力作用，其机械能是守恒的．学.科.网 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 2.实验原理 图7－9－1 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 学.科.网 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 三、探究步骤 1.安装置：将打点计时器固定在铁架台上；用导线将打点计时器与低压交流电源相连接． 2.接电源，打纸带：把纸带的一端在重物上用夹子固定好，另一端穿过打点计时器的限位孔,用手提着纸带使重物停靠在打点计时器附近，接通电源，待打点稳定后松开纸带，让重物自由下落．重复几次，打下3～5条纸带． Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. 要点探究·讲练互动 实验数据处理 学.科.网 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (2012·金陵中学高一检测)某同学做验证机械能守恒定律实验时，不慎将一条挑选出的纸带一部分损坏，损坏的是前端部分．剩下的一段纸带上各相邻点间的距离已测出标在图7－9－3中，单位是cm.已知打点计时器工作频率为50 Hz，重力加速度g取9.8 m/s2. 图7－9－3 例1 Evaluation only. Created with Aspose.Slides for .NET 3.5 Client Profile 5.2.0.0. Copyright 2004-2011 Aspose Pty Ltd. (1)重物在2点的速