Question

Applying brakes stop a train in certain distance. When the braking force is made one fourth, the brakes will stop the same train in a distance, which is now:

• A. same
• B. four times
• C. double
• D. half

Answer 1

The correct option is B four times

We know that braking force is inversely proportional to braking distance covered.
$i.e.F\propto \frac{1}{s}$

$\therefore \frac{s_2}{s_1}=\frac{F_1}{F_2}$

$\therefore \frac{s_2}{s_1}=\frac{F_1}{F_1/4}$

$\therefore \frac{s_2}{s_1}=4$

$\therefore s_2=4\times s_1$