Question

Jack and jill exercise in a 25.0-m-long swimming pool. jack swims nine lengths of the pool in 2 minutes and 32.1 seconds, while jill, the faster swimmer, covers ten lengths in the same time interval. find the average velocity and average speed of each swimmer.

Answer 1

Average Speed

Jack swims nine lengths of a 25 meter long swimming pool in 2 minutes and 32.1 seconds.

So, total distance
`=(25*9)meters= 225 meters` and time
`=(60*2+32.1)seconds=152.1 seconds`

Thus, average speed of Jack
`=(Distance)/(Time)=(225)/(152.1)meters/second=1.4792...meters/second`

Now, Jill swims ten lengths of the 25 meter long swimming pool in the same time interval.

So, the total distance
`=(25*10)meters=250 meters` and time
`=152.1 seconds`

Thus, average speed of Jill
`=(Distance)/(time)=(250)/(152.1) meters/second=1.6436...meters/second`

Average Velocity

As Jack swims nine lengths of the pool, it means he ends up at the opposite end of the pool from where he started. So, the net displacement = 25 meter

Thus, average velocity of Jack
`=(Displacement)/(Time)=(25)/(152.1) meters/second=0.1643...meters/second`

Now, Jill swims ten length of the pool, it means he ends up at the starting position. So, the net displacement = 0 meter

Thus, average velocity of Jill
`=(Displacement)/(Time)=(0)/(152.1)meter/second= 0` meter/second.