1. The problem statement, all variables and given/known data The ratio of the time periods of small oscillation of the insulated spring and mass system before and after charging the masses is (a) ≥ 1 (b) > 1 (c) ≤ 1 (d) = 1 2. Relevant equations 3. The attempt at a solution First I calculated the time period of neutral masses . Let us consider origin to be at the left of m1 .Take the x axis to be along the length of the spring and call the left mass be m1 at coordinate x1 and right mass be m2 at coordinate x2 . x=x2-x1-L d2x/dt2 = d2(x2-x1)/dt2 EOM for mass m1 is m1d2x1/dt2 = kx EOM for mass m2 is m2d2x2/dt2 = -kx After manipulating the above two equations we arrive at d2/dt2 + (k/μ)x = 0 ,where μ = m1m2/(m1+m2) . The time period is 2π√(μ/k) . Now when the masses are charged , EOM for mass m1 is m1d2x1/dt2 = kx - keq2 / (x+L)2 EOM for mass m2 is m2d2x2/dt2 = -kx + keq2 / (x+L)2 . Is this the correct way to approach the problem ? If yes ,how should I proceed .