Question

Um carro durante um trajeto de 400m sofreu um aumento de velocidade de 20m/s para 40m/s. Sabendo que a massa do veículo soma massa dos seus ocupantes corresponde a 1200 kg, determine a força necessária para proporcionar tal aceleração. Justifique.

Answer 1

V^2=Vi^2+2.α.ΔS

40^2=20^2+2.α.400

α=1,5m/s^2

F=m.α

F=1200.1,5

F=1800N

Answer 2

$\Large\displaystyle\text{ \begin{gathered} \hookrightarrow\boxed{\boxed{\bf F_R=1800~N}}\end{gathered} }$

• Explicação:

$\Large\displaystyle\text{ \begin{gathered} \sf{ v {}^{2} = v _{0} {}^{2} + 2 \cdot a \cdot \Delta s } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ 40 {}^{2} = 20 {}^{2} + 2 \cdot a \cdot400 } \end{gathered} }$

$\Large\displaystyle\begin{gathered} \sf{ 1600 = 400 + 800 \cdot a } \end{gathered}$

$\Large\displaystyle\begin{gathered} \sf{ 800 \cdot a = 1600 - 400 } \end{gathered}$

$\Large\displaystyle\begin{gathered} \sf{ 800 \cdot a = 1200 } \end{gathered}$

$\Large\displaystyle\text{ \begin{gathered} \sf{ a = \frac{1200}{800} } \end{gathered} }$

$\Large\displaystyle\begin{gathered} \sf{ a = 1,5\,m/s^2 } \end{gathered}$

$\Large\displaystyle\begin{gathered} \sf{F_R = m \cdot a } \end{gathered}$

$\Large\displaystyle\begin{gathered} \sf{F_R = 1200 \cdot 1,5 } \end{gathered}$

$\Large\displaystyle\text{ \begin{gathered} \boxed{ \boxed{\sf{F_R = 1800 \: N }}} \end{gathered} }$