LESSONS: Energy
The majority of lesson ideas below require minimal resources other than the smartphone, and are relevant to introductory physics in high school and college. However, creative individuals are using smartphone science in more complex ways, with drones, engineering kits, and much more. Follow us on Twitter @PhysicsToolbox and see our Publications page for additional content.
Potential and Kinetic Energy of a Pendulum
What is the relationship between POTENTIAL ENERGY and KINETIC ENERGY of a simple pendulum?
Try This
Using the Accelerometer tool, fix the smartphone to the end of a simple pendulum made from a string attached to a point. Before releasing the pendulum from a given height (measured from the bottom of the pendulum swing), determine the potential energy using the mass of the smartphone and a ruler. Release the smartphone. Using data from the acceleration when at the lowest point, determine the tangential velocity at the lowest point (and hence, the kinetic energy).
Challenge Yourself
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How did the starting potential energy at the top of the swing compare to the kinetic energy at the bottom of the swing?
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How would this relationship differ if potential energy had been measured from the ground, and not from the bottom of the pendulum swing? Why?
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Draw energy pie charts for systems in which potential energy is measured from both frames of reference.
Related Resources
Energy in Magnetic Fields and Solar Flares
Where does energy "go" when magnets and their fields interact?
Try This
Using the Magna-AR setting that makes use of the magnetometer, accelerometer, and gyroscope, visualize how fields change when magnetic poles are brought together. Read about the implications magnetic field energy has for how stars release energy into space.
Related Resources
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Teacher Guide: Energy in Magnetic Fields and Solar Flares
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Student Worksheet: Energy in Magnetic Fields and Solar Flares
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Learn more about Magna-AR on our Project Page