Answer:
.39 m/s
Explanation:
The total mechanical energy must be conserved, which means the amount of elastic potential energy to start with will convert to kinetic energy. That means we can set kinetic energy and spring elastic potential energy equal to each other.
KE = 1/2mv² and SE = 1/2kx²
1/2(770)(v²) = 1/2(950)(.35²), v = .39 m/s