What is the spring force constant k for a ball dropped onto a spring?

[irbombardmnt]

Please help me out, I'm new here, and I only have one more attempt on this problem, totally lost.

Homework Statement

A(n) 142 g ball is dropped from a height of 62.2 cm above a spring of negligible mass. The ball compresses the spring to a maximum displacement of 4.35501 cm. The acceleration of gravity is 9.8 m/s^2 . Calculate the spring force constant k. Answer in units of N/m.

Homework Equations

F=-kx

The Attempt at a Solution

mgh=-kx
(.142)(9.8)(.622)=-k(0.435501)
k=19.875

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[Gear300]

You're setting energy equal to force. Instead of the force of the spring, use the potential energy of the spring.

 

[rl.bhat]

Hi irbombardmnt, welcome to PF.
Your relevant equation is not correct. mgh is the fall of potential. kx is not the energy.
What is the formula for the energy stored in a stretched spring?
In fact ball falls through h+x distance before it comes to rest.