Calculating Max Speed of 0.3 kg Mass on Horizontal Spring

[flynostrich08]

Homework Statement

If a mass of 0.3 kg is attached to a horizontal spring system with a spring constant of 32 N/m^2 is stretched 0.2 m from its relaxed length, what is the maximum speed the mass will attain when released from this position?

The Attempt at a Solution

i thought all you end up with is Vf=squareroot of k/m(xi^2-xf^2) but it is wrong.

 

[Doc Al]

When the mass is at its maximum speed, what will be the stretch of the spring?

 

[mo_0820]

$$x_i=?\mbox{ and }x_f=?{ },{ }\mbox{how do you think?}$$
$$\mbox{does the statement is complete? frictional force?}$$