Alright let's start this off with our basic equation!
Accerlation (a) = ?
Initial velocity (V1)= 26 m/s
Final velocity (V2) = 0 ft/s because the car comes to a complete stop!
Time (t) = 6 seconds
The equation for acceleration is below!
a = [tex] \frac{Final velocity - Initial Velocity}{time} [/tex]
So now, just plug in the values!
a = [tex] \frac{0 - 26}{6} [/tex]
a = [tex] \frac{-26}{6} [/tex]
a = -4.33 m/s²
Therefore, your acceleration is -4.33 m/s²!! Hope this helped and was one of the branliest answers :')