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

Answer

A, B

Explanation

(a) Velocity=slope of s-t graph
`:.` Sign of velocity=sign of slope s-t graph
(b) Let us discus any one of them, let the portion
cd, slope of s-t graph (=velocity) of this
region is negative but increasing in magnitude.
Therefore sign of velocity and acceleration
both are negative.