Question

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

Answer 1

Given that,

Total distance $D=100m$

Now, Time taken to cover $60m$ with a velocity $20m/s$,

$t_1=\frac{60}{20}$

$t_1=3s$

Time taken to cover $40m$ with a velocity $10m/s$,

$t_2=\frac{40}{10}$

$t_2=4s$

Now, the average velocity

$v_{avg}=\frac{\text{Displacemnt (D)}}{\text{Total time taken}(t_1+t_2)}$

$v_{avg}=\frac{100}{7}$

$v_{avg}=14.29m/s$

Hence, the average velocity is $14.29m/s$