Use the following information for questions 18 - 21. A 0.13 kg disk is rotating at an angular speed of 57 rad/s. The disk has a radius of 0.25 m. The disk speeds up for 3 s. After the 3 s have passed, the edge of the disk is under a centripetal force of 312.13 N. What is the centripetal acceleration of the disk at this time