Answer: Option B
:
B
The average speed is given by the ratio of the total distance travelled to the total time taken.
During a round trip,
The total distance travelled = length of the path $\ne 0$
$\therefore$ the average speed $\ne 0$
Also, the object comes back to the same point from where it has started the journey. So, the total displacement of the object is zero. The average velocity is given by the ratio of the total displacement to the total time taken.
$\therefore$ the average velocity $=0$
Hence, the average velocity is zero for a round trip.