5-3 할리데이 11판 솔루션 일반물리학

$$ \begin{cases} m&=1000\ut{kg}\\ t&=1.8\ut{s}\\ v&=1400\ut{km/h}=\frac{3500}{9}\ut{m/s} \end{cases} $$ $$\Sigma \vec F = m\vec a,$$ $$ \begin{aligned} \Sigma \vec F &= m\frac{\Delta v}{t}\\ &=\frac{17500000}{81}\ut{N}\\ &\approx 216049.3827160494\ut{N}\\ &\approx 2.2\times10^5\ut{N}\\ \end{aligned} $$