In this paper we study the asymptotic behavior of solutions of the following nonautonomous wave equation with nonlinear dissipation. $$\left\{\begin{array}{ll} u_{tt}+\vert u_{t}\vert^{\alpha}u_{t}-\Delta u +f(u)=g(t,x),\quad{\rm in}\,\mathbb{R}_{+}\times\Omega,\\ \qquad\qquad u(t,x)=0,\quad\, {\rm on}\,\mathbb{R}_{+}\times\partial\Omega,\end{array}\right.$$ where f is an analytic function, α is a small positive real and g(t, ·) tends to 0 sufficiently fast in L 2(Ω) as t tends to ∞. We also obtain a general convergence result and the rate of decay of solutions for a class of second order ODE containing as a special case $$\left\{\begin{array}{ll} \ddot{U}(t)+\Vert\dot{U}(t)\Vert^{\alpha}\dot{U}(t)+\nabla F(U(t))=g(t),\quad t \in \mathbb{R}_+,\\ \qquad U(0)=U_{0}\,\in \mathbb{R}^{N},\quad\dot{U}(0)=U_{1}\in \mathbb{R}^{N}. \end{array}\right.$$