Question

Two car travelling towards each other on a straight road at velocity $10m/\sec$ and $12m/\sec$ respectively. When they are $150m$ apart, both drivers apply their brakes and each car decelerates at $2m/{\sec }^2$ until it stops. How far apart will they be when they have both come to a stop?

• A. 8.9 m
• B. 89 m
• C. 809 m
• D. 890 m

Answer 1

Answer: (B)

Let $x_1$ and $x_2$ be the distance travelled by the car before they stop under deceleration.
Using the formula $v^2=u^2+2as$,
we have, $0=(10{)}^2-2\times 2\times x_1$
and $0=(12{)}^2-2\times 2\times x_2$
Solving we get,
$x_1=25$ metre and $x_2=36$ metre
Total distance covered by the two cars
$x_1+x_2=25+36=61$ metre
Distance between the two cars when they stop
$=150-61=89$ metre