3. A metre rule is balanced by masses 100g and 25g hanged at 0cm mark and 100cm mark respectively. If the metre rule has a mass of 40g, determine the position of the pivot for the system to be balanced. (3marks)

summing moments about the 0cm end.

100*0+25*100 +40*50 -(100+25+40)*x=0
x=distance from 0 cm end= (2500+2000)/165=27.3cm measured from the 0 cm end (100g hanging there). check my math.