In simple harmonic motion (SHM), the general equations for position, velocity, and acceleration are:
x(t) = A cos(ωt + φ)
v(t)  = 

=  A ω sin(ωt + φ) 
a(t)  = 

=  A ω^{2} cos(ωt + φ) 
The phase angle φ is determined by the initial position and initial velocity.
The constant multiplying the sine or cosine represents the maximum displacement. Thus:
x_{max} = A v_{max} = Aω a_{max} = Aω^{2}
Graphing the position, velocity, and acceleration reveal general features of SHM:
The first set of graphs is for ω = 1 rad/s. The second set is for ω = 0.6 rad/s. This change of ω is accomplished either by decreasing the spring constant or by increasing the mass. Which change was made in this case?