The displacement of a particle starting from rest (at $t = 0$) is given by $s = 6{t^2} – {t^3}$. The time in seconds at which the particle will attain zero velocity again, is ….. $\sec$

From the following displacement-time graph find out the velocity of a moving body

The motion of a particle is described by the equation $x = a + b{t^2}$ where $a = 15\, cm$ and $b = 3 \,cm/s^2$. Its instantaneous velocity at time $3\, sec$ will be……..$cm/sec$

Two cars $P$ and $Q$ start from a point at the same time in a straight line and their positions are represented by $ x_p(t)=at+bt^2 $ and $x_Q(t)= ft- t^2$. At what time do the cars have the same velocity $?$