Question

A boy starts from a point $O$ and travels $50m$ in $30s$. He returns back to the same point $O$ in $20s$. Calculate the average velocity of the boy.

• A. $1m{s}^{-1}$
• B. $5m{s}^{-1}$
• C. $0m{s}^{-1}$
• D. $2m{s}^{-1}$

Answer 1

The correct option is C $0m{s}^{-1}$

Since the boy starts from point $O$, and returns to the same point, the total displacement of the boy is $0m$.
As we know,
$\text{Average velocity}=\frac{\text{Total displacement}}{\text{Total time}}$
or, $v=\frac{0}{30+20}=0m{s}^{-1}$

Therefore, average velocity of the boy is zero.