A 2.2-kg block is attached to a spring of stiffness \(1000 \mathrm{~N} / \mathrm{m}\) and slides on a surface that makes an angle of \(7^{\circ}\) with the horizontal. When displaced from equilibrium and released, the decrease in amplitude per cycle of motion is observed to be \(2 \mathrm{~mm}\). Determine the coefficient of friction.