Figure 3.24 gives the x-t plot of a particle in one-dimensional motion. Three different equal intervals of time are shown. In which interval is the average speed greatest, and in which is it the least? Give the sign of average velocity for each interval.
From the graph,
It is clear that slope of x-t graph is maximum in interval 2 and minimum in interval 3. The interval which covers more lengthy line will have maximum average speed. Thus, average speed is maximum in interval 3.
If slope in x-t graph is positive average speed is positive and slope in x-t graph is negative average speed is also negative.
∴ In interval 1 average speed is positive.
In interval 2 average speed is positive.
In interval 3 average speed is negative.
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