An automobile travelling with speed of $60 \mathrm{~km} / \mathrm{h}$, can brake to stop within a distance…
An automobile travelling with speed of $60 \mathrm{~km} / \mathrm{h}$, can brake to stop within a distance of $20 \mathrm{~cm}$. If the car is going twice as fast, i.e $120 \mathrm{~km} / \mathrm{h}$, the stopping distance will be
$20 \mathrm{~m}$
$40 \mathrm{~m}$
$60 \mathrm{~m}$
$80 \mathrm{~m}$
Solution
If the initial speed is doubled, the stopping distance becomes four times, i.e. $80 \mathrm{~m}$.