Solving for Coefficient of Kinetic Friction

[RedGuitar]

Homework Statement

You push a 2.0 kg block against a horizontal spring, compressing the spring by 15 cm. When you release the block, the spring forces it to slide across a tabletop. It stops 75 cm from where you released it. The spring constant is 200 N/m. What is the coefficient of kinetic friction between the block and the table?

Homework Equations

Ki + Uspi = Kf + Uspf

The Attempt at a Solution

i've already set Ki=0 and Uspf=0, but I'm having trouble finding the Vf

 

[durt]

So you store energy in the spring, which is then transferred to the block. It then loses this energy and stops. Where did it go?

 

[RedGuitar]

what do you mean where did it go?

the block stopped 75 cm from where it was released