Question

a truck is moving at 25m/s speed slows down to 15m/s over a distance of 20m . Find the retardation produced by the brakes.

Answer 1

Dear student,
Given,
Initial velocity, u=25m/s
Final velocity after retardation, v= 15m/s
Distance = 20m
Retardation produced by the brakes, a=?
Using third equation of motion,
$$\begin{gathered} v^2-u^2=2as \\ (15{)}^2-(25{)}^2=2a\left(20\right) \\ 225-625=40a \\ -400=40a \\ a=-10m/s^2 \\ Negativesignindicatesretardation. \\ Regards \end{gathered}$$