A laboratory balance uses a uniform beam XY XY\,XY of length 0.8 m, pivoted at its centre. A uniform circular disc has diameter 0.2 m and mass 120 g. The disc is placed flat on the beam with one edge aligned with end XXX. A calibration mass of M M\,M grams is suspended from end YYY. The beam is horizontal and in equilibrium.
Find MMM.
State how the assumption that the disc is uniform has been used.
42 exam-style questions on WJEC A Level Maths 4.10 Moments (A-level only), covering 4.10.1 Moments (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.