Mass attached to vertical spring

[sualeh]

Homework Statement

an object of mass 0.4kg is attached to horizontal spring of ,,spring constant 80N/m,,and it is displaced 0.1m from equilibrium postion and released from rest,,such that it perform up and down simple harmonic motion.find its velocity when it passes through equilibrium point

Homework Equations

k.e=kinetic energy...k.e=0.5><(mg)^2/k...

3. The attemp at a solution
solving above equation will give,,v=0.7,,,but in solution key it is 1.4m/s ref(serway physics vol 8..ch#13,pg451,,ques,4

 

[CAF123]

Sketch a free body diagram for the mass and write NII for its motion. Then use the initial conditions to find the position of the mass as a function of t, from which you can obtain its velocity as a function of t.