Posted by Brandon on .
An unknown mass is suspended by a string from
one end of an uniform stick which has a mass of
120 g. In order to balance the stick, it must be
supported one third of its length away from the mass. the unknown mass is therefore?

Physics 
drwls,
Let m be the unknown mass and M be the stick's mass. Stick length = L . The center of mass is L/6 from the fulcrum. The total moment about the fulcrum is zero.
m*g*(L/3) = M*g*(L/6)
m = M/2 = 60 g