You are provided with a uniform metre rule, a knife edge, some masses and other necessary apparatus.
(i) Determine and record the centre of gravity of the metre rule.
(ii) Fix the 100 g mass marked N at a point Y, the 80 cm mark of the rule using an adhesive.
(iii) Suspend another 100 g mass marked M at X, a distance A = 10 cm from the 0 cm mark of the rule.
(iv) Balance the arrangement horizontally on the knife edge as shown in the diagram above.
(v) Measure and record the distance B of the knife edge from the 0 cm mark of the rule.
(vi) Repeat the procedure for four other values of A = 15, 20, 25, and 30 cm.
(vii) Measure and record the corresponding values of B in each case. Tabulate your readings.
(viii) Plot a graph of B on the vertical axis against A on the horizontal axis.
(ix) Determine the slope, s, of the graph. Also determine the intercept, c, on the vertical axis.
(x) Evaluate (A) = k1 = 1 – 2s 100;
(B) = k2 = 2c 160.
(xi) State two precautions taken to obtain accurate results. [21 marks]
(b) (i) Define moment of a force about a point. [2 marks]
(ii) State two conditions under which a rigid body at rest remains in equilibrium when acted upon by three non-parallel coplanar forces [2 marks]