Displacement and Density

sharonita

Heres the question:
A 6.8-kg piece of metal displaces 1 liter of water when submerged. Calculate its density.

So I have no idea where to begin or how the displacement relates to the density. What can you suggest? Thanks!

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sharonita

i reallllyy need help =\
anybody?

Erwin Schrodinger

Density equals mass divided by volume. If the object displaces 1 liter of water, then it has a volume of 1 liter. You also have to know that 1 liter = 0.001 cubic meters. The objects density is 6.8kg/0.001m^3 or 6800kg/m^3.

sharonita

But wasnt the weight 6.8kg?

Erwin Schrodinger

Yes the mass is 6.8kg and the volume is 1liter which is equal to 0.001m^3. The density is mass divided by volume which is 6.8kg/0.001m^3. Do 6.8 divided by 0.001 on a calculator; what answer do you get?

cepheid

Staff Emeritus
Gold Member
sharonita said:
But wasnt the weight 6.8kg?

Nope, the mass was 6.8 kg. The kilogram is a unit of mass, not weight.

6800...thanks!

sharonita

ohhhh. okay thanks a bunch!
im such a newbie, thats all. :)

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