Question

um carro durante um trajeto de 400m sofre um aumento de velocidade de 20m/s para 40m/s.sabendo que a massa do veículo somada à massa de seus ocupantes corresponde a 1200kg.determine a força necessária para proporcionar tal aceleração

Answer 1

Δs=400m
Vo=20m/s
V=40m/s
m=1200Kg

V²=Vo²+2a.Δs
(40)²=(20)²+2a.400
1600=400+800a
800a=1200
a=1200/800
a=12/8----> (3/2)m/s²

F=m.a
F=1200.(3/2)
F=1800N

Answer 2

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

• Explicação:

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

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

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

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

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

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

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

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

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

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