Uploaded August 2026 | Updated September 2026, 2 weeks ago
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For small amplitudes of motion, the small-angle approximation can be applied to the restoring torque exerted by gravity on a simple pendulum. Therefore, the motion of a pendulum with a small angular displacement can be modeled as simple harmonic motion because the restoring torque is proportional to the angular displacement. The period of a simple pendulum is related to its length and the magnitude of the gravitational field.
Sections:
00:00 - Simple vs physical pendulums
00:44 - Analyzing forces on a simple pendulum
02:49 - Restoring torque on a simple pendulum
05:56 - Small-angle approximation reveals SHM
09:45 - Position-time graph of a simple pendulum
10:35 - Energy of a simple pendulum
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Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now. khanacademy.org/science/ap-physics-c-mechanics
For small amplitudes of motion, the small-angle approximation can be applied to the restoring torque exerted by gravity on a simple pendulum. Therefore, the motion of a pendulum with a small angular displacement can be modeled as simple harmonic motion because the restoring torque is proportional to the angular displacement. The period of a simple pendulum is related to its length and the magnitude of the gravitational field.
Sections:
00:00 - Simple vs physical pendulums
00:44 - Analyzing forces on a simple pendulum
02:49 - Restoring torque on a simple pendulum
05:56 - Small-angle approximation reveals SHM
09:45 - Position-time graph of a simple pendulum
10:35 - Energy of a simple pendulum
------------------
Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help!
Donate here: khanacademy.org/donate?utm_source=youtube&utm_medium=desc
Volunteer here: khanacademy.org/contribute?utm_source=youtube&utm_medium=desc
