A car traveling at 30m/s screeches to a halt, leaving 55 m long skid marks. what was the cars acceleration while braking

For this problem we use the derived equations for rectilinear motion at constant acceleration. The equation is written below:

2ax = v² - v₀²

where

a is the acceleration

x is the distance

v is the final velocity

v₀ is the initial velocity

Since the car comes to a stop eventually, v=0. Substituting the values,

2a (55) = 0² - 30²

a = - 8.18 m/s²