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 =

So now, just plug in the values!
a =

a =

a = -4.33 m/s²
Therefore, your acceleration is -4.33 m/s²!! Hope this helped and was one of the branliest answers :')
PE = mgh
Mass, m = 7kg, g ≈ 10 m/s², height = 2m
= 7*10*2
= 140 Joules.
I think it is D
Hope my answer help you?