Work energy theorem to find the maximum compression

[negatifzeo]

Homework Statement

A 6.0 kg box moving at 3.0 m/s on a horizontal, frictionless surface runs into a light spring of force constant 75N/cm. Use the work energy theorem to find the maximum compression of the spring.

Homework Equations

Wtotal=K2-K1

k1=1/2mv^2=27 J

The Attempt at a Solution

I mus tbe missing something conceptually here, this doesn't appaear to be a difficult problem but I just don't know how to approach it. I don't know the total work, how do I find it?

 

[slider142]

Can you find the kinetic energy of the box before it hits the spring?

 

[mgb_phys]

At the maximum compression the box stops
So all the initial Ke is now spring energy.
What's the equation for energy stored in a spring in terms of spring force and extention?