An object of mass \( 0.2 \, \text{kg} \) executes simple harmonic motion along x-axis with frequency of \(\displaystyle \left( \frac{25}{\pi} \right) \, \text{Hz} \). At the position \( x = 0.04 \, \text{m} \) the object has kinetic energy \( 0.5 \, \text{J} \) and potential energy \( 0.4 \, \text{J} \). The amplitude of oscillation is ______ \( \text{cm} \).
