Another look at a damped physical pendulum

A calculus-based physics course does not ordinarily discuss damped harmonic motion with a constant damping force. Nevertheless, the model developed in this note is well within the expertise of a student who is familiar with damped harmonic motion and who has some experience with solving ordinary differential equations. Calculations can be performed easily with a spreadsheet and compared with measurements that have been taken with a data acquisition system. Although we have applied the model to the motion of a physical pendulum where the damping is due to sliding friction in a variable resistor, students can apply the model to measurements made on other damped harmonic oscillators. © 2005 American Association of Physics Teachers.