Solving for Damping Coefficient of Pendulum

[dezzz]

Homework Statement

A 82.0 cm pendulum is released from a small angle. After 112 oscillations the amplitude
is one half of its original value. The damping is proportional to the speed of the
pendulum bob. Find the value of the damping coefficient, α, (in Hz).

Homework Equations

x = Ae^-bt/2m cos(wt + phaseangle)

w = root(g/L)

 

[gneill]

Hi dezzz, welcome to Physics Forums.

The pendulum has a second order differential equation just like that of an RLC circuit. You might want to peruse the http://en.wikipedia.org/wiki/RLC_circuit" for some ideas. Pay particular attention to the bit about the Q of the system; it is related to the energy lost per cycle.