Question

A body covers the first $1/3$ of the distance with a velocity of $2\text{m/s}$, the next $1/3$ with $3\text{m/s}$ and the rest of the distance with $6\text{m/s}$. The average velocity in $\text{m/s}$ for covering the whole distance is (assume that the body travels with constant velocity in all the parts in a straight line)

• A. $3$
• B. $\frac{11}{3}$
• C. $\frac{8}{3}$
• D. $\frac{4}{3}$

Answer 1

The correct option is A $3$

Total distance of the journey =$d$
Total time taken for the journey = $\frac{\frac{d}{3}}{2}+\frac{\frac{d}{3}}{3}+\frac{\frac{d}{3}}{6}$
$\therefore$ Average velocity = $\frac{d}{\frac{d}{6}+\frac{d}{9}+\frac{d}{18}}$= $3\text{m/s}$