Search any question & find its solution
Question:
Answered & Verified by Expert
An athelete completes one round of a circular track of radius $R$ in $40 \mathrm{~s}$. What will be his displacement at the end of $2 \min 20 \mathrm{~s}$ ?
Options:
Solution:
1414 Upvotes
Verified Answer
The correct answer is:
$2 R$
The time $=2 \min 20 \mathrm{~s}$
$=2 \min +20 \mathrm{~s}$
$=2 \times 60 \mathrm{~s}+20 \mathrm{~s}=140 \mathrm{~s}$
In $40 \mathrm{~s}$ athelete completes $=1$ round
In $140 \mathrm{~s}$ athelete will completes
$=\frac{140}{40} \text { round }$
$=\frac{120}{40}+\frac{20}{40}$
$=3+\frac{1}{2}$ round
The displacement in 3 round $=0$ So displacement in $\frac{1}{2}$ round $=A B=2 R$
$=2 \min +20 \mathrm{~s}$
$=2 \times 60 \mathrm{~s}+20 \mathrm{~s}=140 \mathrm{~s}$
In $40 \mathrm{~s}$ athelete completes $=1$ round
In $140 \mathrm{~s}$ athelete will completes
$=\frac{140}{40} \text { round }$
$=\frac{120}{40}+\frac{20}{40}$
$=3+\frac{1}{2}$ round
The displacement in 3 round $=0$ So displacement in $\frac{1}{2}$ round $=A B=2 R$
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.