The figure shows an x-t graph of a particle moving along a straight line. What is the sign of the acceleration during the intervals OA, AB, BC, and CD?

a) From the graph we can infer that in the interval OA, it’s almost a straight line with a positive slope. Therefore velocity is positive that is with increase in time distance also increases and thus acceleration is also positive as well as uniform.

b) In the interval AB, the line has a negative slope as with increase in time distance decreases. Here velocity is negative and it shows retardation.

c) BC represents more downfalls in the slope of the line which means velocity will become more negative and hence it shows retardation with greater magnitude than AB.

d) CD shows that with increase in time distance is increasing again with a positive slope. Therefore velocity is positive which implies acceleration is also positive.