The amplitude of a torsional vibration decreases so that the amplitude on the 100th cycle is 13% of the the amplitude of the first cycle. Determine the level of damping in terms of the logarithmic decrement. Is this simply ln(100/13)= 2.04 or ln(13/100)= -2.04?
Level of damping δ = 1/n*ln(x_{o}/x_{n}) where n is the number of cycles, x_{o} is the initial amplitude and x_{n} is the amplitude after n cycles.