3. Use ODE45() to simulate the behavior of two Mass-Spring-Damper systems given the parameters k=[2 or 4], b=0.25, and m = 4.0. Assume there is no input force, but the system starts with a displacement in the x direction of 0.0 and an initial velocity of 4.0. Turn plots (using subplot to create a 2 x 2 set of plots) of the systems' position and velocity for the following time periods: 1, 5, 30, and 60 seconds that illustrate the changes that occur when using different springs. From the graph estimate the natural frequency of the systems. Finally turn in one plot showing the position after 30 seconds where you modify other system parameters. Briefly discuss how the changes in physical properties impacted the system behavior.