Help with energy conservation calculations

Attention physicists, I need help.

First year university physics student here, and I need assistance finding the kinetic energy of an object (specifically, a mousetrap car our lab team built).
I already found the speed, acceleration, net force, and work, we were given the Ek of the mousetrap spring (100N/cm = 1J), I already know the equation to find Ek (1/2 mv^2), and I know energy is conserved, not created, not destroyed, etc.
The question is, using the values I have, how do I complete the energy conservation calculations?

I can provide data from the trials if needed.

In before "lol failure", it's only a bullshit degree breadth course I'm required to take.

>>11
>>12
Wow, same person, you are clearly a genius for being at the right place at the right time to memorise those particular letters.

k means any constant, x could represent anything, not everyone has encyclopedic knowledge of text shorthand and "If you don't know how integrals work" just goes to support my assertion that you are an obscurant douche.