A small electric car has a maximum constant acceleration of $1\,m / s ^2$, a maximum constant deceleration of $2\,m / s ^2$ and a maximum speed of $20\,m / s$. The amount of time it would take to drive this car $1\,km$ starting from rest and finishing at rest is $.........\,s$
$15$
$50$
$35$
$65$
A car moving along a straight highway with speed of $126 \;\mathrm{km} h^{-1}$ is brought to a stop within a distance of $200\; \mathrm{m}$. What is the retardation of the car (assumed uniform in $m/s^2$) ?
A particle starts with initial speed $u$ and retardation a to come to rest in time $T$. The time taken to cover first half of the total path travelled is .......