8-76 할리데이 11판 솔루션 일반물리학

$$ \put \begin{cases} \KE : \text{Kinetic Energy}\\ \GE : \text{Gravitational Potential Energy}\\ \TE : \text{Thermal Energy}\\ \end{cases} $$ $$ \begin{cases} S&=6.00\ut{m}\\ F&=2.00\ut{N}\\ f&=10.0\ut{N}\\ \Delta \KE&=+40.0\ut{J} \end{cases} $$ $$\Sigma \Delta E=W_F,$$ $$\Delta \KE+\Delta \GE+\Delta \TE=W_F$$ $$ \begin{aligned} W_G&=-\Delta \GE\\ &=\Delta \KE+\Delta \TE- W_F\\ &=\Delta \KE+fS-FS\\ &=\Delta \KE+S(f-F)\\ &=40+6\cdot(10-2)\\ &=88\ut{J}\\ &=88.0\ut{J}\\ \end{aligned} $$