What is the relation between displacement, time and acceleration in case of a body having uniform acceleration
$S = ut + \frac{1}{2}f{t^2}$
$S = (u + f)\;t$
$S = {v^2} - 2fs$
None of these
Two cars leave one after the other and travel with an acceleration of $0.4\, m/s^2$. Two minutes after the departure of the first, the distance between the cars becomes $1.9\, km$. The time interval between the departures of the cars is ........$s$
A point starts moving in a straight line with a certain acceleration. At a time $t$after beginning of motion the acceleration suddenly becomes retardation of the same value. The time in which the point returns to the initial point is