The equation of motion of a particle, wheresis in meters andtis in seconds, is given by the equation below.

$\displaystyle s = 5t^3 - 4t$

i know that

$\displaystyle v(t) = 15t^2 - 4$

and

$\displaystyle a(t) = 30t$

The question is "Find the acceleration when the velocity is 0. (Round the answer to one decimal place.)"

I feel dumb asking this cause it seems like an easy problem, but i have no clue what the answer is.