An object starts at x = 0 m on a straight track. It travels 6 m in the positive direction in 3 s, remains still for 5 s, then travels 6 m in the negative direction in 2 s. Each moving stage has constant speed and direction changes take negligible time. Find its final position, total distance, average speed and average velocity for the whole journey. Explain why a moving-stage speed cannot replace the whole-journey average.

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Final position 0 m; distance 12 m; average speed 1.2 m/s; average velocity 0 m/s. Choose the stated positive track direction and preserve the signs. The final coordinate is 6 − 6 = 0 m, which is also the displacement because the starting coordinate is zero. Distance counts every travelled section without cancellation: 6 + 6 = 12 m. The stationary stage adds no distance but still occupies time. The complete elapsed time is 3 + 5 + 2 = 10 s. Therefore average speed is total distance divided by this time: 12/10 = 1.2 m/s. Average velocity uses signed displacement instead: 0/10 = 0 m/s. Zero average velocity means return to the start, not absence of motion. The individual moving speeds are 2 and 3 m/s. Neither alone includes both travel stages and the pause, so neither is automatically the correct whole-journey average.

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