College Physics (7th Edition)

a) we know that density $\rho = \frac{M}{V}$ where M is the mass and V is the Volume Volume of the brick $V = L\times b\times\ h$ =$1\ cm\times2\ cm\times 4\ cm = 8\ cm^{3}$ Given density $\rho$ = $9 g/cm^3$ now mass can be calculated by $m = \rho\times V = 8\ cm^3\times 9\ g/cm^3 = 72\ g = 0.072\ kg$ ------------------------------------------ b) cube of this material containing twice the mass of brick, its volume would be twice of the previous one i,e 2V length is $L = (2V)^{1/3} = (2\times 80\ cm^3)^{1/3} = 2.52\ cm$