Question

What is the velocity of the simple harmonic motion problem?

Position of the graph is
y= .4*cos(2pi*1/3*x)+1.2

I need to find the velocity as well as the acceleration. I have worked through it and keep getting that the velocity is 0. I don't believe that is correct.

Answer 1

You do not have time in your equation, only a solid unmoving cosine function.
Do you mean t instead of x ?

y = .4 cos[ (2 pi/3) t ] + 1.2 ?

if so then

dy/dt = v = -.4(2 pi/3) sin[ (2 pi/3) t ]

a = d^2y/dt^2 = -.4(2 pi/3)^2 cos[ (2 pi/3) t ]
which is
a = - (2pi/3)^2 * y