Doubling which quantity would cause the largest increase in a spring’s elastic potential energy?

A spring’s elastic potential energy is U = ½kx², where k is the spring constant and x is its displacement from equilibrium. Doubling k doubles the energy, but doubling x multiplies the energy by four because displacement is squared. Mass and gravitational acceleration do not appear in this spring-energy formula. Therefore, doubling displacement causes the largest increase.

AI-written and checked against the verified answer.