Hi there!
Recall the equation for Spring Potential Energy:
[tex]\large\boxed{PE = \frac{1}{2}kx^2}[/tex]
PE = Potential Energy (J)
k = Spring Constant (N/m)
x = displacement from equilibrium (m)
Plug in the givens:
[tex]PE = \frac{1}{2}(200)(0.02^2) = 0.04 J[/tex]
All of the potential energy will be converted to kinetic energy when the spring is released, so:
[tex]\large\boxed{KE = 0.04 J}[/tex]
