How far was the spring stretched from its unstreched length?

A mass m = 10 kg rests on a frictionless table and accelerated by a spring with spring constant k = 4777 N/m. The floor is frictionless except for a rough patch. For this rough path, the coefficient of friction is μk = 0.43. The mass leaves the spring at a speed v = 3.8 m/s.
so I got .17... but it's not correct, I used 3.8 sqrt(10/4777)
what am I doing wrng?

1 answer

1/2 k x^2 = 1/2 m v^2 ... x = v √(m / k) ... x = 3.8 √(10 / 4777)

significant figures are the only thing that comes to mind
... the mass is one sig fig ... so the result should be also