Respuesta :
[tex]-4\frac{m}{s^2}[/tex]
Explanation
the acceleration is the change of velocity in a determined tiem, it can be found by using the expression
[tex]\begin{gathered} g=\frac{\Delta velocity}{\Delta time}=\frac{v_f-v_i}{\text{time taken}} \\ g=\frac{v_f-v_i}{\text{time taken}} \\ \text{where} \\ v_i\text{ is the initial velocity} \\ v_f\text{ is the final velocity} \\ \end{gathered}[/tex]so
let
[tex]\begin{gathered} v_f=0\text{ (rest)} \\ v_i=40\text{ }\frac{mi}{h} \\ \text{time}=\text{ 10 sec} \end{gathered}[/tex]replace in the expression
[tex]\begin{gathered} g=\frac{v_f-v_i}{\text{time taken}} \\ g=\frac{0-40\frac{mi}{h}}{10\text{ s}} \\ g=\frac{-40\frac{mi}{h}}{10\text{ s}}=-4\frac{mi}{s^2} \\ g=-4\frac{mi}{s^2} \end{gathered}[/tex]therefore, the answer is
[tex]-4\frac{mi}{s^2}[/tex]I hope this helps you
