$A$ constant force of friction of $50 \ N$ is acting on a body of mass $200 \ kg$ moving initially with a speed of $15 \ m \ s^{-1}$. How long does the body take to stop? What distance will it cover before coming to rest?

(N/A) Given: Force $F = -50 \ N$ (retarding force),mass $m = 200 \ kg$,initial velocity $u = 15 \ m \ s^{-1}$,final velocity $v = 0 \ m \ s^{-1}$.
$1$. Calculate acceleration $(a)$:
Using Newton's second law,$F = ma$,so $a = F / m = -50 / 200 = -0.25 \ m \ s^{-2}$.
$2$. Calculate time $(t)$:
Using the first equation of motion,$v = u + at$,we get $0 = 15 + (-0.25)t$.
$0.25t = 15$,therefore $t = 15 / 0.25 = 60 \ s$.
$3$. Calculate distance $(S)$:
Using the second equation of motion,$S = ut + 1/2 at^2$.
$S = (15 \times 60) + 1/2 \times (-0.25) \times (60)^2$.
$S = 900 - 0.125 \times 3600 = 900 - 450 = 450 \ m$.