For a short time the arm of the robot is extending such that  when r = 3 ft, z = (4t2) ft,...

For a short time the arm of the robot is extending such that  when r = 3 ft, z = (4t2) ft, and θ = 0.5t rad, where t is in seconds. Determine the magnitudes of the velocity and acceleration of the grip A when t = 3 s.