An athlete completes one round of a circular track of radius $\mathrm{R}$ in $40 \mathrm{sec}$. What will be…
An athlete completes one round of a circular track of radius $\mathrm{R}$ in $40 \mathrm{sec}$. What will be his displacement at the end of 3 min. $20 \mathrm{sec}$ ?
Zero
$2 \mathrm{R}$
$2 \pi R$
$7 \pi R$
Solution
Total time of motion is $3 \min 20 \mathrm{sec}=200 \mathrm{sec}$. As time period of circular motion is $40 \mathrm{sec}$ so in $200 \mathrm{sec}$ athlete will complete 5 revolutions i.e., he will be at starting point
i.e., displacement $=$ zero.
Asked in: JEE Mains - Motion In One Dimension - Test 1