6 A uniform lamina OABC is in the shape of a trapezium where O is the origin of the coordinate system in which the points \(A , B\) and \(C\) have coordinates \(( 12,0 ) , ( 12 + p , q )\) and \(( 0 , q )\) respectively.
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- Determine, in terms of \(p\) and \(q\), the coordinates of the centre of mass of OABC .
The point D has coordinates \(( 7.6 , q )\). When OABC is suspended from D , the lamina hangs in equilibrium with BC horizontal.
- Determine the value of \(p\).
When OABC is suspended from C, the lamina hangs in equilibrium with BC at an angle of \(35 ^ { \circ }\) to the downward vertical.
- Determine the value of \(q\), giving your answer correct to \(\mathbf { 3 }\) significant figures.