When a car driver travels at the speed of $10m/s$ applies brake and brings the car to rest in $20sec$. then the retardation will be?

Step 1: Given data

$\mathrm{u}=10\mathrm{m}/\mathrm{s}$

$\mathrm{v}=0$

$\mathrm{t}=20\sec$

Step 2: Formula used

1. Acceleration is defined as the rate at which an object's velocity changes over time.
2. Acceleration can be given as$\mathrm{a}=\frac{(\mathrm{v}-\mathrm{u})}{\mathrm{t}}$, where $u$ is the initial velocity, $v$ is the final velocity, and $t$ is the time taken by an object.

Step 3: Calculating the acceleration

By putting the values in the formula

$$\begin{gathered} \mathrm{a}=\frac{(0-10)}{20} \\ =-0.5{\mathrm{ms}}^{-2} \end{gathered}$$

Therefore, the retardation is $0.5m/s^{-2}$.