Question

Displacement-time graph of a particle moving in a straight line is as shown in figure. Find the sign of velocity in regions $oa$, $ab$, $bc$ and $cd$.

Answer 1

Slope of the displacement-time graph gives the velocity of the particle.

Region $oa$ : Slope is positive and increasing with time.

$\therefore$ Velocity of particle is $(+)$ and increasing.

Region $ab$ : Slope is positive and constant with time.

$\therefore$ Velocity of particle is $(+)$ and constant.

Region $bc$ : Slope is positive and decreasing with time.

$\therefore$ Velocity of particle is $(+)$ but decreasing.

Region $cd$ : Slope is negative and increasing in magnitude with time.

$\therefore$ Velocity of particle is $(-)$ but its magnitude increases.