A particle oscillating under a force $\overrightarrow{\mathrm{F} }=-\mathrm{k}\overrightarrow{\mathrm{x}} -\mathrm{b}\overrightarrow{\mathrm{v}}$ is a (k and b are constants)

A particle oscillating under a force $\overrightarrow{\mathrm{F} }=-\mathrm{k}\overrightarrow{\mathrm{x}} -\mathrm{b}\overrightarrow{\mathrm{v}}$ is a damped oscillator. the first term $-\mathrm{k}\overrightarrow{\mathrm{x}}$represents the restoring force and second term $-\mathrm{b}\overrightarrow{\mathrm{v}}$ represents the damping force.