2 The region \(R\) is bounded by the \(x\)-axis, the lines \(x = a\) and \(x = 2 a\), and the curve \(y = \frac { a ^ { 3 } } { x ^ { 2 } }\) for \(a \leqslant x \leqslant 2 a\), where \(a\) is a positive constant. A uniform solid of revolution is formed by rotating \(R\) through \(2 \pi\) radians about the \(x\)-axis. Find the \(x\)-coordinate of the centre of mass of this solid.