Question

An athlete completes one round of a circular track of radius $10m$ in $40s$. The distance covered by him in $2$ min $20$ s is :

• A. $110m$
• B. $70m$
• C. $220m$
• D. $140m$

Answer 1

The correct option is

B

$220m$

Time period $=40s$.

No. of revolutions $=\frac{Totaltime}{Timeperiod}$

$=\frac{140s}{40s}$

$=3.5$ Revolutions

So, distance $=3.5\times 2\pi R$

$=3.5\times 2\pi \times 10$

$=220m$