Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information....

The pendulum

Question: Compare the periods of pendula having bobs with different masses.

Solution: From the equation

we might expect that a larger mass would lead to a longer period. However, increasing the mass also increases the forces that act on the pendulum: gravity and the tension in the string. This increases k as well as m, so the period of a pendulum is independent of m.

Last Update: 2009-06-21