For a short time the position of a roller-coaster car along its path is defined by the equations r = 25 m,  = (0.3t) rad, and z = (-8 cos) m, where

For a short time the position of a roller-coaster car along its path is defined by the equations r = 25 m,  = (0.3t) rad, and z = (-8 cos) m, where t is measured in seconds, Determine the magnitudes of the car's velocity and acceleration when t = 4s.