Question

A swimmer travels from the south end to the north end of a 30.0 m pool in 15.0 s and makes the return trip to the starting position in 19.0 s. What is the average velocity for the second half of the swim?

Answer 1

The practical formula for average velocity is:
\[\frac{final position - initial position}{elapsed time}\]

Answer 2

So, the second half of this swim is going from the north end to the south end. So, your initial position will be the 30m you first swam to, and the final position will be 0m.