Gujarati
Hindi
7. MOTION
medium

A motor bike running at $90\, km h ^{-1}$ is slowed down to $18 \,km h^{-1}$ in $2.5\, s$. Calculate

$(i)$ acceleration

$(ii)$ distance covered in the time it slows down

Option A
Option B
Option C
Option D

Solution

$u=90 km h ^{-1}=25 m s ^{-1} ; v=18 km h ^{-1}=5 m s ^{-1}$

$t=2.5 s ; a=? ; S =?$

$(i)$ Applying $v=u+a t$

$5=25+a \times 2.5$

$-20=2.5 \times a$

Or $a=\frac{-20}{2.5}=-8 m s ^{-2}$

$(ii)$ Applying $v^{2}-u^{2}=2 a S$

$(5)^{2}-(25)^{2}=2 \times(-8) \times S -600=-16 S$

or $S=\frac{600}{16}=37.5 m$

Standard 9
Science

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.