Chapter 2 - Kinematics in One Dimension - Exercises and Problems - Page 64: 15

$a=-1.2ms^{-2}$

We have initial velocity $ u=8.0m/s$ final velocity $v=6.0m/s$ distance travelled in between change of velocity$ s=5m$ We know that $2as=v^2−u^2 $ ∴ $a=\frac{v^2−u^2}{2s}$ $a=\frac{(6.0)^2 - (8.0)^2}{2*(5.0)}ms^{-2}$ $a= \frac{36-48}{10} ms^{-2}$ $a=-1.2ms^{-2}$