I learn that damping force with regard to forced damped oscillations is given by F = -bv where is the velocity of the object measured from ground frame. Suppose we are in a frame which is moving with a velocity v'. Will the damping force in this new frame be F = -b(v-v') or will it remain -bv. This doubt came when i solving a problem related to forced damped oscillation of a pendulum with its suspension point oscillating. Im arriving at the correct solution by assuming the force is -bv in the non-inertial frame of the moving suspension point instead of -b(v-v') but im not able to understand why?