Viscous Damper:
A viscous damper contains viscous friction and it translates energy into heat because of this. For this damper force is proportional to the relative velocity.
Fd α relative velocity (v)
∴ Fd = cv
here c is constant of proportionality and it is known as coefficient of damping. The coefficient of viscous damping is represents as the force in 'N' while velocity is 1 m/s.