A Typical Application In case the differential equation models a physical system, the nonhomogenous term F(x)frequently corresponds to some external influence on the system. 4口1日，1元2000A Typical Application In case the differential equation models a physical system, the nonhomogenous term F(x) frequently corresponds to some external influence on the system. Suppose that a mass m is attached both to a spring that exerts on it a force FS and to a dashpot (shock absorber) that exerts a force FR on the mass. Assume that the restoring force FS of the spring is proportional to the displacement x (positive to the right, negative to the left) of the mass from equilibrium, and that the dashpot force FR is proportional to the velocity v = dx/dt of the mass. Then we have FS = −kx and FR = −cv (k, c > 0)