(a) Explain how you can use the graph of position versus time in Figure 2.54 to describe the change in velocity over time. Identify (b) the time ( ta , tb , tc , td , or te ) at which the instantaneous velocity is greatest, (c) the time at which it is zero, and (d) the time at which it is negative.
The graph indicates the plot of position versus time.
The slope of the curve will give the velocity.
It can be checked that, the graph is not a straight line with some angle. So, the velocity is not changing.
If the graph would have been like a slanted straight line, it denotes uniform velocity.