Direct Measurement Videos > Video Library > Conservation of energy in a pendulum

Conservation of energy in a pendulum


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A small pendulum swings. Students can measure the height of the pendulum above the equilibrium position, and the speed of the pendulum as it passes the equilibrium point. They can use these measurements to compare the mechanical energy at various times during the motion.


Instructor Note

When teaching with this video, direct students to the student video library, which provides student access to all videos without links to instructor materials and solutions.

Three file formats are available to work with this video. For analysis in class, frame-by-frame viewing is needed.

DMV player

Download (Quicktime Video 6.3MB Jun27 14)


Teaching Materials

Note that the mass of the pendulum bob is 450 grams.

Suggested Questions:

  • What is the kinetic energy during the first pass?
  • What is the maximum gravitational potential energy of the bob (-earth system) when the bob is at the high point.
  • What percent loss of mechanical energy during each swing?
  • What is the increase in thermal energy of the system?