Question

A boy walks for 1 minute at a speed of 1 m/s and then runs for 1 minute at a speed of 3 m/s along a straight track. Calculate the average speed of the boy.

Answer 1

Step 1:Given data:

Initially, the speed of the boy, $v_1=1m/s$ and time, $t_1=1minute.$

Finally, the speed of the boy, $v_2=3m/s$ and time, $t_2=1minute.$

Let, $v_{avg}$ be the average speed of the boy.

Now,

the total time of walks by the boy,

T = 1+1 = 2 minutes = 120 seconds.

Step 2:Finding the total distance traveled by the boy:

$Dis\tan ce\left(s\right)=Speed\times time$

And total distance traveled by the boy,

$$\begin{gathered} s=v_1\times t_1+v_2\times t_2 \\ ors=\left(1\times 60\right)+\left(3\times 60\right)=240m. \\ ors=240m. \end{gathered}$$

Step 3:Finding the average speed:

We know,

$$\begin{gathered} Averagespeed=\frac{Totaldis\tan ce}{Totaltime}. \\ or{v}_{avg}=\frac{240}{120}=2m/s. \\ or{v}_{avg}=2m/s. \end{gathered}$$

Therefore, the average speed of the boy is 2 m/s.