In the diagram, an aluminium sheet has uniform thickness. Four notable points on the aluminium sheet are marked P, Q, R and S. How can the centre of mass be determined?
- Aby finding where a line from P to R crosses a line from S to Q
- Bby suspending the sheet and a plumb-line from Q and finding where the plumb-line crosses a line from P to R
- Cby suspending the sheet and a plumb-line from P and then from S and finding where the plumb-lines cross
- Dby suspending the sheet and a plumb-line from P and finding where the plumb-line crosses a line from S to Q