Question

An automobile in travelling at 50 km/h, can be stopped at a distance of 40 m by applying brakes. If the same automobile is travelling at 90 km/h, all other conditions remaining same and assuming no skidding, the minimum stopping distance in metres is:

• A. 72
• B. 92.5
• C. 102.6
• D. 129.6

Answer 1

Answer: (D)

129.6

Answer 2

$s\propto {{u}^{2}}$ $\Rightarrow$ $\frac{{{s}_{2}}}{40}={{\left( \frac{90\times \frac{5}{18}}{50\times \frac{5}{18}} \right)}^{2}}$ $\Rightarrow$ ${{s}_{2}}=129.6\,m$