Question

Consider that a truck is moving initially with $54\, Km / h$. It has stopped by the driver after looking at an obstacle with a deceleration of $10\, m / s ^{2}$. The distance travelled by truck before coming to rest is

• A. 12 m
• B. 11.25 m
• C. 11.30 m
• D. 11.20 m

Answer 1

Answer: (B)

Given, initial velocity of truck, $u=54\, km / h$
$=54 \times \frac{5}{18}=15\, m / s$
Final velocity, $v=0$
Deceleration, $a=-10\, m / s ^{2}$
As we know that,
$v^{2}=u^{2}+2 a s$
$\Rightarrow (0)^{2}=(15)^{2}+2 \times(-10) s$
$\Rightarrow 20\, s=(15)^{2}$
$s=\frac{15 \times 15}{20}=11.25\, m$