Hello, run into a bit of a stumbling block studying moments perhaps someone could nudge me in the right direction. 1. The problem statement, all variables and given/known data A uniform metre ruler is balanced horizontally on a knife edge at its 350mm mark, by placing a 3.0N weight on the rule at its 10mm mark. Calculate the weight of the ruler. 2. Relevant equations Not entirely certain but I have to assume it involves Moments = force x perpendicular distance and the principle of moments. 3. The attempt at a solution This is where I'm stuck I've reasoned (probably wrongly) that: (3N x 0.34m) + (y x b) = (z x a) and y + z = the weight of the ruler. Where y is the weight of the 350mm long side of the ruler b is the distance between where the force y is acting (which I'm assuming is just its midpoint) and the pivot z is the weight of the 650mm side of the ruler. a is the distance between where the force z is acting (which again I'm assuming is its midpoint) and the pivot. Not only am I extremely doubtfull that my above formula is correct I can't really see any way that I can determine the weight of the ruler form the information I've been given. Any help would be greatly appreciated.