Elasticity and simple harmonic motion

[peaches1221]

A mass sitting on a horizontal, frictionless surface is attached to one end of a spring; the other end is fixed to a wall. 3 J of work is required to compress the spring by 0.12 m. If the mass is released from rest with the spring compressed 0.12 m, it experiences a maximum acceleration of 19 m/s2. Find the value of the mass.

I'm not sure if this is right, I just wanted to check my work.

step1: find k
step 2: find m

3= 1/2 K (.12)^2
k= 417 N/m

then i simply used kx= ma
417(.12)= m (19)
solved for m and I got 2.63... Is that right even though they say amax is 19?

 

[G01]

Your work looks correct to me.