Posted by Anonymous on .
A copper (Cu) weight is placed on top of a 0.24 kg block of wood (density = 0.60 103 kg/m3) floating in water. What is the mass of the copper if the top of the wood block is exactly at the water's surface?

Physics ASAP!! 
bobpursley,
I will be happy to critique your thinking.

Physics ASAP!! 
Anonymous,
well i'm thinking to find the mass I need to find the volume of copper but i don't have any info to find that so i have no idea what to do

Physics ASAP!! 
Elena,
Density of wood is ρ₁=600 kg/m³,
density of water is ρ₂=1000 kg/m³,
m=0.24 kg,
M=?
The volume of the wooden block is
V=m/ρ₁=0.24/600=4•10⁻⁴ m³.
Mg+mg=F(buoyancy)
Mg+mg= ρ₂•V•g
M= ρ₂•V m =1000•4•10⁻⁴0.24=0.16 kg