Calculus Based (Projectile)

The position of the front bumper of a test car under microprocessor control is given by x(t)=2.17m+(4.80m/s^2)t^2•-(0.100m/s^6)t^6. Find the position and the acceleration at the instants when the car has zero velocity.

Please help meeee.

Not sure what all those m's and s's are, but I'll assume they're just units (which make no sense as written), and

x(t) = 2.17 + 4.80t^2 - 0.10t^6
v(t) = dx/dt = 9.60t - 0.600t^5
So, v=0 when t = 0 or t=2
And, of course, a(t) = 9.6 - 3.00t^4
So plug in your t values as needed.