Average Speed And Average Velocity

Average speed is defined as total distance divided by total time, while average velocity is total displacement divided by total time. These two quantities are conceptually distinct because speed depends on the entire path length, but velocity depends only on the net change in position. For one complete lap, the jogger travels a distance equal to the full circumference, 400 m, so the average speed is $400/100=4\text{ m/s}$. However, since the jogger finishes at the same point where the lap began, the net displacement over the lap is zero, giving an average velocity of $0/100=0\text{ m/s}$. The option 4 m/s and 4 m/s is wrong because it incorrectly equates displacement with distance. The option 0 m/s and 4 m/s simply swaps the two results. The option 2 m/s and 2 m/s uses a wrong distance value. This mirrors the NCERT distinction between scalar and vector kinematic averages. As a plausibility check, average velocity for any closed loop must be exactly zero because the position vector returns to its initial value.