7. Figure 3 shows a pendulum bob at position X. It is then released and it swings to position Y and then Z.

(a) Describe the energy contained in the pendulum bob when it is at the following positions. Explain briefly your answers.
(i) X:
(ii) Y:
(iii) Z:

(b) Describe the energy change when the pendulum bob swings from.
(i) X to Y:
(ii) Yto Z:​