Question

A boy walksf rom his classroom to the book shop along a straight corridor towards North. He covers a distance of 20 m in 25 seconds to reach the bookshop. After buying a book, he travels the same distance in the same time to reach back in the classroom. Find Average velocity.

Answer 1

The boy starts his journey from the classroom and ends his journey in the same classroom. So, the initial position and the final position of the boy is the same.
The formula for average velocity is displacement/time taken
Displacement is the difference between the final position and the initial position . So, the displacement covered is zero. So, average velocity is also zero.

Answer 2

the boy comes back to its position ( classroom)
so displacement is zero and velocity=displacement\ time
so average velocity is zero