To make a pendulum, a 300 g ball is attached to one end of a string that has a length of 1 .4 m and negligible mass. (The other end of the string is fixed.) The ball is pulled to one side until the string makes an angle of 30.0o with the vertical; then (with the string taut) the ball is released from rest. Find
(a) The speed of the ball when the string makes an angle of 20.0' with the vertical and
(b) The maximum speed of the ball.
(c) What is the angle between the string and the vertical when the speed of the ball is one-third its maximum value?