Simple Harmonic Motion find Mass

[mhz]

Homework Statement

A block is attached to a horizontal spring with k = 75 N/m undergoes SHM with an amplitude of 0.15m. If the speed of the block is 1.7 m/s when the displacement is 0.12m from equilibrium, what is the mass of the block?

Homework Equations

E = E'
E_{k} = \frac{1}{2}mv^{2}
E_{s} = \frac{1}{2}kx^{2}

The Attempt at a Solution

E = E'
E_{k1} + E_{s1} = E_{s2}
\frac{1}{2}mv^{2} + \frac{1}{2}kx^{2} = \frac{1}{2}kx^{2}
Where subscript 1 indicates that x = 0.12 m and subscript 2 indicates that x = 0.15 m (max energy)
Substituting in ...
m = 0.21 kg

but the answer is 0.27 kg?

 

[OldEngr63]

With that data, the answer is m = 0.21 kg.