1. Given that \(AD\) is the diameter of a circle and \(AB\) is a chord such that \(AD= 34cm\) and \(AB=30 cm\), calculate the distance of the chord \(AB\) from the centre of the circle.
2. If in a circle, \(OA=5 cm\) and \(AB=8 cm\), and the radius \(OD\) is drawn perpendicular to the chord \(AB\), determine the length of \(CD\).
