Question

A car decelerates from a speed of 20 m/s to rest in a distance of 100 m .What was its acceleration ,assume constant ?

Answer 1

$$\begin{gathered} u=20m/s \\ v=0 \\ s=100m \\ {v}^2-u^2=2as \\ 0-400=2\times a\times 100 \\ a=-2m/s^2 \end{gathered}$$