Question

A car travelling at a speed 72 km/hr is brought to rest in 40 sec. Find the distance travelled by the car before coming to rest ​

Answer 1

$\huge\red{Answer}$→$s_{1st} =19m$

           →$s_{3rd} =15m$

$\huge\purple{Explanation}$→$u_{initial}$ =72×  $\frac{5}{18}$ =20m/s

$a_{dec}$=2m/s²

 (a)s=ut+  $\frac{1}{2}$at²

v=u+at

v=0

u−$a_{dec}$t=0

20=2×1

t=10s

s=20×10−  $\frac{1}{2}$×2×100

s=100m

(b)t=10s

(c)$s_{nth}$ =u+  $\frac{a}{2}$ (2n−1)

$s_{1st}$=20− $\frac{2}{2}$ (2×1−1)

$s_{1st}$=19m

$s_{3rd}$ =20− $\frac{2}{2}$ (2×3−1)

$s_{3rd}$=15m

$\huge\orange{@alurringbabe}$