Question

When the speed of a car is $v$, the minimum distance over which it can be stopped is $s$. If the speed becomes $nv$, what will be the minimum distance over which it can be stopped during the same time?

• A. $s/n$
• B. $ns$
• C. $s/n^2$
• D. $n^{2}s$

Answer 1

Answer: (D)

$n^{2}s$

$0-v^2=2as\Rightarrow a=\frac{-v^2}{2s}0-{\left(nv\right)}^2=2ad\Rightarrow -{\left(nv\right)}^2=2\times \frac{-v^2}{2s}\times d\Rightarrow d=n^{2}s$