The Simple Pendulum

• A simple or ideal pendulum has a point-mass bob and massless string
• For small angles (less than 15 degrees), the restoring force is proportional to the displacement from rest
• So pendula exhibit simple harmonic motion iff they are displaced slightly from the vertical
• The period of an ideal pendulum depends only on its length and the local acceleration due to gravity
• A more realistic model is the physical pendulum, consisting of a string with mass and an extended bob
• The physical pendulum's period depends on its moment of inertia, its mass, the distance from the pivot to its center of mass, and the local acceleration due to gravity

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