physics
posted by kelly .
The amplitude of an oscillator decreases to 69.0% of its initial value in 15.5s.
a) What is the value of the time constant?

If the time constant is T,
A(t) = A(0) e^(t/T)
0.69 = e^(15.5/T)
Take natural logs of both sides.
ln(0.69) = 0.3711 = 15.5/T
T = 41.8 s