The density of aluminium is 2700kg/m^-3.calculate the mass of a block of aluminium which has a volume of 100cm3?


1 Answer
Oct 1, 2017

The mass of the block is 0.270 kg.


There is one error in the problem as written up.
Density = mass/volume, therefore the units should be
either #(kg)/m^3 or kg*m^-3#.

This will require converting the volume units from #cm^3 " to " m^3.# I will use a method I call "multiplying by 1" that I have used since my first Physics class. You may go to this site for an explanation of my method:

Converting #100 cm^3# step by step:
#100 cm^3 * ((1 m)/(100 cm))^3 #
#100 cm^3 * (1 m)^3/(10^2 cm)^3#
#1*10^2 cm^3 * (1 m^3)/(10^6 cm^3)#
#1*cancel(10^2) cancel(cm^3) * (1 m^3)/(10^4*cancel(10^2) cancel(cm^3)) = 1*10^-4 m^3#

Density = mass/volume, therefore one algebraic operation will tell us that
mass = density*volume. So, the last step to finding your answer is

#"mass" = (2700kg)/cancel(m^3) * 1*10^-4 cancel(m^3) = 0.270 kg#

I hope this helps,