Question 2.9: A meter rile is supported on a knife edge placed at the 40cm graduation. It is found that the meter rule balances horizontally when a mass which has a weight of 0.45 N is suspended at the 15cm graduation. As shown in the diagram.

a) Calculate the moment, about the knife edge in this balanced condition, of the force due to the mass of the rule.
b) If the weight of the rule is 0.90N, calculate the position of its center of gravity.