The acceleration-time graph for a body is shown in the graph. Which of the following  graphs would probably represent velocity of the body plotted against time:-

The maximum possible acceleration of a train moving on a straight track is $10\  m/s^2$ and maximum possible retardation is $5 \ m/s^2.$ If maximum achievable speed of train is $10\ m/s$ then minimum time in which train can complete a journey of $135\ m$ starting from rest and ending at rest, is.........$s$

The velocity of a bullet is reduced from $200\,m/s$ to $100\,m/s $ while travelling through a wooden block of thickness $10\,cm$. The retardation, assuming it to be uniform, will be 

A dancer moves counterclockwise at constant speed around the path shown below. The path is such that the lengths of its segments, $PQ, QR, RS$, and $SP$, are equal. Arcs $QR$ and $SP$ are semicircles. Which of the following best represents the magnitude of the dancer’s acceleration as a function of time $t$ during one trip around the path, beginning at point $P$ ?

Which of the following speed-time $(v-t)$ graphs is physically not possible?

If the velocity of a particle is given by $v = {(180 - 16x)^{1/2}} m/s$, then its acceleration will be.......$ms^{-2}$