2-45 할리데이 11판 솔루션 일반물리학

$$x=50t+10t^2$$ $$\ab{a}$$ $$ \begin{aligned} \bar v_{0\rarr3}&=\frac{\Sigma \Delta x_{0\rarr3}}{\Sigma \Delta t_{0\rarr3}}\\ &=\frac{x(3)-x(0)}{3}\\ &=\frac{(240)-(0)}{3}\ut{m/s}\\ &=80\ut{m/s}\\ &=80.0\ut{m/s}\\ \end{aligned} $$ $$\ab{b}$$ $$ \begin{aligned} v&=\dxt{x}\\ &=\dt\(50t+10t^2\)\\ &=50+20t \end{aligned} $$ $$ \begin{aligned} a&=\dxt{v}\\ &=\dt\(50+20t\)\\ &=20\\ \end{aligned} $$ $$ \begin{aligned} a(3.00)&=20\ut{m/s^2}\\ &=20.0\ut{m/s^2}\\ \end{aligned} $$ $$\ab{c}$$ $$ \begin{aligned} v(3.00)&=50+20\cdot(3.00)\\ &=110\ut{m/s}\\ &=1.10\times10^2\ut{m/s}\\ \end{aligned} $$

$$\ab{d}$$

$$\ab{e}$$

$$\ab{f}$$