1. The problem statement, all variables and given/known data A spring (which tension is k) is connected with a body (which mass is m). The whole system is in viscous liquid. In this liquid frictional force is proportional to speed: F = -C*v. With what C value the oscillation won't happen? 3. The attempt at a solution The damping ratio is defined as dr = c / (2 * sqrt(k * m)). No oscilation will happen when there is critical damping dr = 1 or when there is overdamping dr > 1. So: C >= sqrt(4mk); Is the solution above right?