An external harmonic force F whose frequency can be varied, with amplitude maintained constant, acts in a vertical direction on a ball suspended by a weightless spring, the damping coefficient is q times less than the natural oscillation frequency coo of the ball. How much, in per cent, does the mean power (P) developed by the force F at the frequency of displacement resonance differ from the maximum mean power (P) max? Averaging is performed over one oscillation period.