Derive the system of differential equations describing the straight-line vertical motion of the coupled spring shown in Figure 1. Use Laplace transform to solve the system when k 1 = k 2 = k 3 = 1 {\displaystyle k_{1}=k_{2}=k_{3}=1} , m 1 = m 2 = 1 {\displaystyle m_{1}=m_{2}=1} , and x 1 ( 0 ) = 0 {\displaystyle x_{1}(0)=0} , x ′ 1 ( 0 ) = − 1 {\displaystyle x'1(0)=-1} , x 2 ( 0 ) = 0 {\displaystyle x_{2}(0)=0} , and x 2 ′ ( 0 ) = 1 {\displaystyle x'_{2}(0)=1} .