Question

A boy swims in a 100 m long pool. He covers 60 m with a velocity of 20 m/s and covers the rest of the distance with a velocity of 10 m/s. Calculate the average velocity of the boy.

Answer 1

Given :

Total distance travelled =100m
Time taken to cover 60m distance :
Time=distance/speed  or displacement/time
=60/20
=3sec

Time taken to cover next 40m :
time=distance/speed or displacement/time
=40/10
=4sec
Total time=3+4=7sec

Average velocity=Total displacement/magnitude of distance]/total time
=100m/7sec
=14.28m/s

∴The average velcoity =14.28m/s

Answer 2

Total distance:100m  Total time :60/20=3+..40/10=4..=7m/s Average velocity=100/7=14.2m/s