A single-degree-of-freedom system consists of a mass, a spring, and a damper in which both dry friction and viscous damping act simultaneously. The free-vibration amplitude is found to decrease by \(1 \%\) per cycle when the amplitude is \(20 \mathrm{~mm}\) and by \(2 \%\) per cycle when the amplitude is \(10 \mathrm{~mm}\). Find the value of \((\mu N / k)\) for the dry-friction component of the damping