Take the acceleration due to gravity to be 9.81 ms ? where needed 8. The diagram shows a uniform lamina with a circular hole. 4 mi A O 4 m D I m O E The six corners have coordinates 0(0,0), A(0,4), B(4,4), C(4,1), D(8,1) and E(8,0) and are all right angles, The radius of the circle is 0.3 m and its centre has coordinates (3,3). All distances are measured in metres. The mass per unit area is pkg in 2. (a) Show that the total mass is (20 - 0.09m )p kg. (2 marks) (b) Find the coordinates of the centre of mass of the lamina. (6 marks) (c) The lamina is freely suspended in equilibrium from corner A. Find the angle between AO and the vertical. (3 marks) Total marks for this question: 11