12. Figure shows a pendulum at mean position X. It is pulled to the position Y and released. It swings from Y to Z and back to Y. 12 (a) Fill the following statement. "To move the bob from X to Y ................has to be done on it and its .......................energy increases. On moving from Y to X some of this energy is converted into .............energy. Through out the swing from Y to Z and back to Y, the total energy is ......................... *