2-48 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} a&=50.0\ut{m/s^2}\\ v&=80.0\ut{km/h} \end{cases} $$ $$ \begin{aligned} 80\ut{km/h}&=80\ut{km/h}\cdot\frac{1000\ut{m}}{1\ut{km}}\cdot\frac{1\ut{h}}{3600\ut{s}}\\ &=\frac{200}{9}\ut{m/s} \end{aligned} $$ $$ v=v_0+at,$$ $$ \begin{aligned} \frac{200}{9}\ut{m/s}&=(0)+(50\ut{m/s^2})t\\ t&=\frac{4}{9}\ut{s}\\ &\approx 0.4444444444444444\ut{s}\\ &\approx 0.444\ut{s}\\ &\approx 444\ut{ms}\\ \end{aligned} $$