Fig. 2 (NCT).9 show the ` x-t` plot of a particle in one dimensional motion. Three different equal intervals of time are shown. In which interval the average speed is greatest and in which it is the least ? Give the sign of average speed for each interval.
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Explanation

We kinow that aveage speed in a sma,, interval of time is eqqual to the slope of ` x-t` graph in that ineraval of time. The average speed is the greatest in the interval `3` because slope is greatest and the average speed is leaset in inerval `2` necause slope is least there.
The average speed is positive in intervals ` 1` and `2` because slope of ` x-t` is positive there and average speed is negative in interval ` 3` becauses the slpe of ` x-t` is negative.