Question

Mr. Mangan runs 50 m north in 5 seconds, 50 m east in 7 seconds, and50 m south in 3 seconds. What is his average speed? What is hisaverage velocity?

Answer 1

Mr. Mangan goes first in the north a distance

`d_1=50\text{ m}`

at time,

`t_1=5\text{ s}`

then towards east ,

`d_2=50\text{ m}`

in time,

`t_2=7\text{ s}`

after that he goes towards south a distance,

`d_3=50\text{ m}`

in time,

`t_3=3\text{ s}`

the average speed is,

`\begin{gathered} s=\frac{total\text{ distance }}{\text{total time}} \\ =(50+50+50)/(5+7+3) \\ =10\text{ m/s} \end{gathered}`

The average velocity is,

`v=\frac{displacement}{\text{total time}}`

Here the displacement is,

`d^(\prime)=50\text{ m}`

The average speed is,

`\begin{gathered} v=(50)/(5+7+3) \\ =3.33\text{ m/s} \end{gathered}`

The average velocity is,

`v=3.33\text{ m/s along east}`