4. A uniform lamina of mass \(M \mathrm {~kg}\) is modelled as the region which is bounded by the curve with equation \(y = x ^ { 2 }\), the positive \(x\)-axis and the line with equation \(x = 2\). The unit of length on both axes is the metre. Find the moment of inertia of the lamina about the \(x\)-axis.
(6)