Spring Compression on an incline

[luvey]

Homework Statement

A 11kg box slides 4.0m down the frictionless ramp which has an incline of 30^o to the horizontal, then collides with a spring whose spring constant is 190 N/m.

a.What is the maximum compression of the spring?
b.At what compression of the spring does the box have its maximum speed?

Homework Equations

Spring: PE=1/2*k($$\Delta$$s)²
Gravity: PE=mgsin($$\theta$$)d
PE_{spring initial}+PE_{gravity initial}=PE_{spring final}+PE_{gravity final}

The Attempt at a Solution

I tried plugging in the numbers which gave me:
0+11*9.81*sin(30)*4=1/2*190($$\Delta$$s)²+11*9.81*sin(30)*(4+$$\Delta$$s)
Which gave me the max compression of 0.56795 m

I haven't made it to part b yet because I can't seem to obtain the max compression.

 

[rock.freak667]

The Attempt at a Solution

I tried plugging in the numbers which gave me:
0+11*9.81*sin(30)*4=1/2*190($$\Delta$$s)²+11*9.81*sin(30)*(4+$$\Delta$$s)
Which gave me the max compression of 0.56795 m

I haven't made it to part b yet because I can't seem to obtain the max compression.

You do not need the extra 11*9.81*sin(30) on the right side.

The left side is the initial energy which when it reaches the spring is being entirely stored as elastic potential energy.