1-9 할리데이 11판 솔루션 일반물리학

$$\begin{cases} \rho_A &= 10\ut{EA/U.S.~pint}\\ \rho_B &= 30\ut{EA/U.S.~pint}\\ V &= 1.0\ut{m}\times20\ut{cm}\times20\ut{cm}\\ 1\ut{U.S.~pint}&=0.4732\ut{L} \end{cases}$$ $$\begin{aligned} V&=100\cdot20\cdot20\ut{cm^3}\\ &=40000\ut{cm^3} \end{aligned}$$ $$\begin{aligned} \Ans &= N_B - N_A \\ &=\rho_B \cdot V - \rho_A \cdot V\\ &= V\(\rho_B - \rho_A\)\\ &=40000\ut{cm^3}\cdot20\ut{EA/U.S.~pint}\times \cfrac{1\ut{L}}{1000\ut{cm^3}}\times\cfrac{1\ut{U.S.~pint}}{0.4732\ut{L}}\\ &=1690.61707523\ut{EA}\\ &\approx1.7\times10^3\ut{EA} \end{aligned}$$