a). So get linear velocity, the relation is as follows,
v = R*w
where v is linear velocity, w is final angular velocity and R is the radius.
You know the radius but you don't know the final angular velocity.
To get the final angular velocity, the relation is as follows,
w = wo + α*t
where w is final angular velocity, wo is the initial velocity, α is the angular acceleration, and t is the time.
We need to find initial angular velocity,
θ = wo*t + (1/2)α*t
you can find the wo from the above equation and the you the can find the w and then you can find the v.
b. To find the linear acceleration, use the following relation,
at = Rα
c. To find the final centripetal acceleration,
a = v2/R
use the v that you calculated in part a.
Hope it helps, let me know if you have any questions.