Question

Consider that a truck is moving initially with $54Km/h$. It has stopped by the driver after looking at an obstacle with a deceleration of $10m/s^2$. 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, $u=54km/h$
$=54\times \frac{5}{18}=15m/s$
Final velocity, $v=0$
Deceleration, $a=-10m/s^2$
As we know that,
$v^2=u^2+2as$
$\Rightarrow (0{)}^2=(15{)}^2+2\times (-10)s$
$\Rightarrow 20s=(15{)}^2$
$s=\frac{15\times 15}{20}=11.25m$