A laboratory balance uses a uniform beam XY XY\,XY of length 0.6 m which is pivoted at its centre.
A circular silicon wafer of diameter 120 mm and mass 80 g is placed on the beam so that its edge is exactly level with the end XXX. A calibration mass of M M\,M grams is suspended from the end Y Y\,Y by a light inextensible string.
The beam rests horizontally in equilibrium.
Find the value of MMM.
State one assumption you have made about the silicon wafer.
53 exam-style questions on AQA A Level Maths 3.4 S: Moments (A-level only), covering 3.4.1 Moments in static contexts (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.