Question

How long will it take a car to go from 28 m/s to a stop if the average acceleration is -4m/s²?

Answer 1

Given

Initial velocity, u=28 m/s

Final velocity, v=0 m/s

Average acceleration,

`a=-(4m)/(s^2)`

To find

The time taken

Step-by-step explanation:

We know acceleration is the ratio of change in velocity to the time taken

Thus,

`\begin{gathered} a=(v-u)/(t) \\ \Rightarrow-4=(0-28)/(t) \\ \Rightarrow t=7s \end{gathered}`

Conclusion

The time taken is 7 sec