A beaker filled with water is balanced on the left pan of a balance. A cube of 4 cm on an edge is attached to a string and lowered into the water so that it is completely submerged. The cube is not touching the bottom of the beaker. A weight of mass m is added to the right pan to restore equilibrium. What is m ? Well i know that the volume of the cube is 64 cm^3 or 6.4x10^-5 m^3. And the buoyancy force would be the density of the water times the volume of the cube times g. But thats all i've gotten pretty much. I've tried using summation of torques about the pivot of the balance, but it just gets me more and more lost. All I need is a step in the right direction. Would i take into consideration the beaker's mass or density? It doesnt really specify it, but I would think it is made of glass and so the density of glass is 2.6 x 10^3 kg/m^3. The density of water is 1000kg/m^3 and i dont know if it is needed either but the density of air is 1.293 kg/m^3. Thanks.