# Simple Harmonic Motion

1. May 8, 2010

### astrozilla

1. The problem statement, all variables and given/known data
A mass on a spring obeys SHM.Given that the mass is initially at the equilibrium position,has an initial velocity of 2m/s,and a nastural frequency of 2 rad/s,Find A and φ
After 13.2 sec whats the displacement of the mass

2. Relevant equations
ψ=Αcos(ωt+φ)

3. The attempt at a solution
Is the initial velocity ,the maximum velocity ? Maybe yes. Is the initial phase (φ) zero ? I think so.

2. May 8, 2010

### Plutoniummatt

the initial velocity IS the maximum velocity, at equilibrium, KE = max, PE = zero.

if you use your notation for the motion of the mass, ie the cosine term, then no, the phase is not zero, it has to be pi/2, because at T=0, psi must be zero because the mass is at equilibrium.

3. May 8, 2010

### astrozilla

Thanks
Problem solved :)