Objective: Confirm the law of equal areas for central force motions (Kepler’s Second Law)
As an example of motion under the influence of a central force, the elliptical motion of a pendulum bob is recorded by the dust-marking method. This produces a trace with time-interval marks, and from the distances between these one can directly measure the velocity of the pendulum bob. Furthermore, it can be shown by a simple graphical analysis that the area swept by the radius vector of the pendulum in each time interval is constant, and is thus independent of the length of the radius vector.
![Experiment: Kepler’s Second Law, 8000537 [UE1030700], Translational motions](/imagelibrary/UE1030700/UE1030700_01_Experiment-Kepler-s-Second-Law.jpg)
![Experiment: Kepler’s Second Law, 8000537 [UE1030700], Translational motions](/thumblibrary/UE1030700/UE1030700_01_1200_1200_Experiment-Kepler-s-Second-Law.jpg)
![Pair of Elastic Balls with Plotting Electrode, 1000779 [U8405630], 选项](/thumblibrary/U8405630/U8405630_01_140_140_Pair-of-Elastic-Balls-with-Plotting-Electrode.jpg)
![通用夹, 1002830 [U13255], 夹具](/thumblibrary/U13255/U13255_01_140_140_通用夹.jpg)
![双联式三脚架座, 1002835 [U13270], 基底](/thumblibrary/U13270/U13270_01_140_140_双联式三脚架座.jpg)
![不锈钢杆 750mm, 1002935 [U15003], 三脚架杆 支架杆](/thumblibrary/U15003/U15003_01_140_140_不锈钢杆-750mm.jpg)
![不锈钢杆 1000mm, 1002936 [U15004], 杆](/thumblibrary/U15004/U15004_01_140_140_不锈钢杆-1000mm.jpg)
![Equipment Set for Powder Tracing, 1000739 [U8400870], 平面运动](/thumblibrary/U8400870/U8400870_01_140_140_Equipment-Set-for-Powder-Tracing.jpg)
![Pendulum with Plotting Electrode, 1000780 [U8405640], 选项](/thumblibrary/U8405640/U8405640_01_140_140_Pendulum-with-Plotting-Electrode.jpg)
![游标卡尺，150 mm, 1002601 [U10071], 长度测量](/thumblibrary/U10071/U10071_01_140_140_游标卡尺-150-mm.jpg)
![带有挂钩的固定夹, 1002828 [U13252], 夹具](/thumblibrary/U13252/U13252_01_140_140_带有挂钩的固定夹.jpg)
![平台夹, 1002832 [U13260], 夹具](/thumblibrary/U13260/U13260_01_140_140_平台夹.jpg)
![15根安全实验导线套件，75mm, 1002843 [U138021], 电循环](/thumblibrary/U138021/U138021_01_140_140_15根安全实验导线套件-75mm.jpg)
![实验用的起重器II, 1002941 [U15020], 抓子游戏](/thumblibrary/U15020/U15020_01_140_140_实验用的起重器II.jpg)
![竖直标尺，1m, 1000743 [U8401560], 长度测量](/thumblibrary/U8401560/U8401560_01_140_140_竖直标尺-1m.jpg)
![Set of Riders for Rulers, 1006494 [U8401570], 长度测量](/thumblibrary/U8401570/U8401570_01_140_140_Set-of-Riders-for-Rulers.jpg)
![维姆胡斯特起电机, 1002967 [U15310], 静电学](/thumblibrary/U15310/U15310_01_140_140_维姆胡斯特起电机.jpg)
![精确的测力计（透明）, 1003106 [U20034], 弹簧秤和弹簧](/thumblibrary/U20034/U20034_01_140_140_精确的测力计-透明.jpg)
![毫秒计数器（230 V，50/60 Hz）, 1012832 [U8533370-230], 数字计数器](/thumblibrary/U8533370-230/U8533370-230_01_140_140_毫秒计数器-230-V-5060-Hz.jpg)
![Lenz's Law Apparatus, 1009959 [U8556012], 感应现象](/thumblibrary/U8556012/U8556012_01_140_140_Lenzs-Law-Apparatus.jpg)
![原生动物教师用多媒体工具包 基础工具包中包含8个项目, 1008719 [W13722-2], 英语](/thumblibrary/W13722-2/W13722-2_01_140_140_原生动物教师用多媒体工具包-基础工具包中包含8个项目.jpg)
![AB0/Rh Blood Typing Refill kit, 1022413 [W55013], 遗传学实验](/thumblibrary/W55013/W55013_01_140_140_AB0Rh-Blood-Typing-Refill-kit.jpg)