Question

A car slows down from a speed of 72 k/h to rest in 25 sec. what is the acceleration of the car in m/s​

Answer 1

$\blue{\bold{\underline{\underline{Answer:}}}}$

$\green{\tt{\therefore{Acceleration=-0.8\:m/s^{2}}}}$

$\orange{\bold{\underline{\underline{Step-by-step\:explanation:}}}}$

$\green{\underline \bold{Given:}} \\ \tt: \implies Initial \: velocity(u) = 72 \: km/h \\ \\ \tt: \implies Final \: velocity( v ) = 0 \: km/h \\\\ \tt: \implies Time( t) = 25 \: sec \\ \\ \red{\underline \bold{To \: Find:}}\\ \tt: \implies Acceleration(a) = ?$

• According to given question :

$\tt \circ \: Initial \: velocity =72 \times \frac{5}{18} = 20 \: m/s \\ \\ \tt \circ \: Final \: velocity = 0 \: m/s \\ \\ \tt \circ \: Time = 25\: sec \\ \\ \bold{As \: we \: know \: that} \\ \tt: \implies v = u + at \\ \\ \tt: \implies 0= 20 + a \times 25 \\ \\ \tt: \implies -20 = 25 \times a \\ \\ \tt: \implies a = \frac{-20}{25} \\ \\ \green{\tt: \implies a =-0.8 \: m/{s}^{2} }$

$\blue{ \bold{some \: related \: formula}} \\ \orange{\tt \circ \: {v}^{2} = {u}^{2} + 2as} \\ \\ \orange{\tt \circ \: s = ut + \frac{1}{2} at^{2} }$

Answer 2

$</p><p>\tt{\orange{\huge{Hello!!! }}}$

$</p><p>\tt{\red{Given \: - }}$

$</p><p>\tt{\purple{U = 72 kmph}}........(1)$

$</p><p>\tt{\green{V = 0 }}.......(2)$

$</p><p>\tt{\orange {T = 25 sec}} .......(3)$

$</p><p>\tt{\blue{---------}}$

$\tt{ \purple{ \boxed{ \boxed{ \implies{ \: a = \dfrac{v - u}{t} =- 0.8 \: m \:per \: sec. }}}}}$

$</p><p>\tt{\blue{---------}}$

Other Formulae :

$\tt{ \purple{ \boxed{ \boxed{ \implies{ \: {V}^2= {U}^2 + 2as}}}}}$

$\tt{ \purple{ \boxed{ \boxed{ \implies{ \: S= ut + \dfrac{1}{2} a{t}^2 }}}}}$