A particle of mass 2m is attached to a fixed wall on its left by a spring with stiffness 2/ and natural length - and a damper with damping constant 2r. The particle is also attached to another fixed wall a distance 5/ from the left hand wall by a spring of stiffness 3/ and natural length . Let a be the distance of the particle from the left-hand wall, as shown in the following diagram. 5/0 3la 2k, 2 -800800 3k, lo 2r 2m 600800 Enter an expression in the box below that gives the right hand side of the equation of motion of the particle (use |_0 to enter lo). 2ma + 2ri + 5kx =