Damped Oscillation: Finding Time Constant

[Wanderer00]

Homework Statement

The amplitude of an oscillator decreases to 36.8% of its initial value in 10.0 s. What is the value of the time constant?

Homework Equations

xmax=Ae^-bt/2m
Time constant= m/b
xmax(t)= Ae^-t/2(timeconstant)

The Attempt at a Solution

I'm not quite sure where to start with this... because the intitial value isn't known so how would I even get the amplitude?

I found a solution that used A(t)=A(0)e^(-kt) and did this: 0.368A(0)=A(0)e^(-10k) and solved for k, however that wasn't right and I'm wondering why they even thought to use that equation.. is it right?

 

[ehild]

The equation is right. But k is not the time constant if it is defined as m/b.

ehild