From the potential energy curve, Umax=21kA210=21k(2)2 ⇒ k = 5 N / m The length of the simple pendulum, L = 4 m Time period of spring, T=2πmk Time period of simple pendulum, T=2πgI The time period of simple pendulum is same as the time period ofthe spring oscillation. ⇒2πgI=2πmk Substituting the values in the above equations, we get 2πg4=2π55g=4 m/s2 ∴ The acceleration due to the gravity on the planet is 4 m/s2.