The graph of an object's motion (along the $x-$ axis) is shown in the figure. The instantaneous velocity of the object at points $A$ and $B$ are $v_A$ and $v_B$ respectively. Then

A person of height $1.6 \mathrm{~m}$ is walking away from a lamp post of height $4 \mathrm{~m}$ along a straight path on the flat ground. The lamp post and the person are always perpendicular to the ground. If the speed of the person is $60 \mathrm{~cm} \mathrm{~s}^{-1}$, the speed of the tip of the person's shadow on the ground with respect to the person is. . . . $\mathrm{cm} \mathrm{s}^{-1}$.

Draw $v\to t$ graph for constant velocity and explain it.

Which one of the following graph for a body moving along a straight line is possible?

The $x$ – $t$ equation is given as $x=2 t+1$ The corresponding $v-t$ graph is