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\includegraphics[max width=\textwidth, alt={}, center]{57f7ca89-f028-447a-9ac9-55f931201e6b-2_467_645_274_749} A uniform semicircular lamina has radius 5 m . The lamina rotates in a horizontal plane about a vertical axis through \(O\), the mid-point of its diameter. The angular speed of the lamina is \(4 \mathrm { rad } \mathrm { s } ^ { - 1 }\) (see diagram). Find

1. the distance of the centre of mass of the lamina from \(O\),
2. the speed with which the centre of mass of the lamina is moving.