Maximum distance spring compressed.

[AnnieD]

A block of mass m = 1.9 kg is dropped from height h = 77 cm onto a spring of spring constant k = 1510 N/m (Fig. 8-38). Find the maximum distance the spring is compressed.

My attempt:
mgh = 1/2kx^2
(1.9)(9.8)(.77) = (.5)(1510)x^2
x = 0.138m

But it's not the correct answer.
What am I doing wrong?

 

[marlon]

gravity is still working on the block when it is compressing the spring

by writing h in your potential energy, you are saying that h is the distance onlong which the block "feels" gravity

you are going to need to add something there...

marlon