Question

An electric train is moving with a velocity of 108km/hr. How much distance will it cover in 30s to bring the train at rest?
(A) 900 m
(B) 1350m
(C) 450 m
(D) 30 m​

Answer 1

$\large\mathscr \color{black}\colorbox{red}{\colorbox{orange}{\colorbox{yellow}{\colorbox{green}{\colorbox{blue}{\colorbox{indigo}{\colorbox{violet}{\underline {ANSWER}}}}}}}}$

${\large\mathbb\color{yellow}{Initial\:velocity(v_i)=108\:Km{hr}^{-1}}}\\{\large\mathbb\color{yellow}{Final\:velocity(v_f)=0\:km{hr}^{-1}}}\\{\large\mathbb\color{yellow}{time(t)=30s}}\\\\{\large\mathbb\color{yellow}{distance(s)=?}}\\\\{\huge\tt\color{cyan}{s=ut+\frac{1}{2}(\frac{v-u}{\cancel{t}}){t}^{\cancel{2}1}}}\\\\{\large\tt\color{cyan}{s={108\times30}+\frac{1}{2}\times(0-108)\times30}}\\\\{\large\tt\color{cyan}{s=3240+\frac{1}{2}\times-3240=\bf\underline{\underline{1620m}}}}$