Question

A car moving with a speed of 50 km/h can be stopped by brakes after at least 6 m. If the same car is moving at a speed of 100 km/h, the minimum stopping distance is:
(AIEEE 2003)

• A. 12 m
• B. 18 m
• C. 24 m
• D. 6 m

Answer 1

The correct option is C 24 m

Assuming a constant, or average acceleration of - $a_{b}m/s^2$ because of braking,
For stoping, $v$ = 0
$\Rightarrow v^2=u^2-2a_{6}s(asa=-a_b)$
$\Rightarrow u^2=2as$
$\Rightarrow s\alpha u^2$
$\Rightarrow \frac{s}{6}=(\frac{100}{50}{)}^2$
$\Rightarrow s=24m$