Calculating the max distance of compression of the spring HELP

[urgent]

Calculating the max distance of compression of the spring please HELP!

Homework Statement

A 2.0 kg block is dropped from a height of 40 cm onto a spring of force constant k = 1960 N/m. The maximum distance the spring is compressed is?

Homework Equations

I Used the equation W=mgh and W=1/2kx^2..

The Attempt at a Solution

i did..
W=2*9.8*0.4
=7.84
then i used
7.84=1/2*1960*x^2
from which i got x=0.0894427191
then i did
7.84*0.0894427191=0.7012309177
then i did
7.84-0.7012309177=7.13879

can anyone please help me tel where i went wrong? because the answer to this question is 10 but i don't know how to get it..please help=].

 

[badphysicist]

There is extra gravitational potential energy from the distance through which the spring drops through while touching the spring. In other words, the total distance that the object drops is 40 cm plus however far the spring compresses.