8-8 할리데이 11판 솔루션 일반물리학

$$ \put \begin{cases} \KE : \text{Kinetic Energy}\\ \TE : \text{Thermal Energy}\\ \end{cases} $$ $$ \put \begin{cases} A:\text{Floor}\\ B:\text{Box}\\ \end{cases} $$ $$ \begin{cases} F&= 22\ut{N}\\ d&= 3.0\ut{m}\\ \Delta \TE_B&=+18\ut{J}\\ \end{cases} $$ $$\Delta \TE=f d,$$ $$ \begin{cases} \Delta \TE_A=f_A d_A\\ \Delta \TE_B=f_B d_B\\ \end{cases} $$ $$\Delta \TE_A=\Delta \TE_B$$ $$ \because \begin{cases} f_A=f_B\\ d_A=d_B\\ \end{cases} $$ $$\because \Delta \TE_A=\Delta \TE_B=+18\ut{J}$$