=+Problem 2.10 Consider the double pendulum where the first mass is connected to an eccentric spring as depicted in Figure 2.18.c. The spring has a stiffness k and is attached at a distance e above the origin of the pendulum. The spring has a natural length equal to a0 and a is its deformed length. Gravity acts in the direction of the x axis. Taking the absolute angles ????1 and

????2 as degrees of freedom,