Answer:

Explanation:
The artificial gravity generated by the rotating space station is the same centripetal acceleration due to the rotational motion of the station, which is given by:

Here, r is the radius and v is the tangential speed, which is given by:

Here
is the angular velocity, we replace (2) in (1):

Recall that
.
Solving for
:

Speed uses distance and velocity uses displacement in its calculation.
For 100 m race, distance = displacement. Hence speed = velocity
For 400m race, distance ≠ displacement. distance = 400m whereas displacement = 0m. Hence speed ≠ velocity
We know average speed =total distance/time taken
So avg speed=(85+63)/(5+5)=14.8km/hr