A trolley weighing 2 kg, moving at a speed of 5 m / s, crashes into a horizontal spring

A trolley weighing 2 kg, moving at a speed of 5 m / s, crashes into a horizontal spring with a stiffness of 1000 N / m. How much will the spring be compressed when the cart comes to a complete stop?

m = 2 kg
V = 5 m / s
k = 1000 N / m
x-?
When the cart stops, all the kinetic energy of the cart will be converted into potential energy of the compressed spring. The kinetic energy of the cart is Ek = m * V ^ 2 / 2. The potential energy of the compressed spring is Ep = k * x ^ 2/2.
Ek = En; m * V ^ 2/2 = k * x ^ 2/2. m * V ^ 2 = k * x ^ 2; x = square root of (m * V ^ 2 / k), x = 0.223 m