Question

Heya !!

♦ Question :-

♦ An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s?

Answer 1

HEY!!

SORRY, But my handwriting is little different or like small kids studying in class 4th or 5th.

IF IT IS INCORRECT THEN PLEASE REPORT IT

Answer 2

$Hey\:There$ !!
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$Given, \: diameter = 200m$
$Therefore, \: radius = \frac{200}{2} = 100m$
$Time \: taken \: to \: complete \: one \: rotation \: = 40s$
$Time \: after \: 2m \: 20s \: = 2 \times 60s + 20s$
$= (120 + 20)s$
$= 140s$

$We \: know \: that, \: velocity \: along \: a \: circular \: path$
$= \frac{circumference}{time}$
$= \frac{2\pi \: r}{40s}$
$= \frac{2 \times 3.14 \times 100m}{40s}$
$= \frac{628m}{40s}$
$= 15.7 \: m/s$

$Since, \: rotation \: in \: 1s \: = \frac{1}{40}$
$Therefore, \: rotation \: in \: 140s = \frac{1}{40} \times 140$
$= 3.5$

$Now \: distance \: covered \: in \: 2m \: 20s \: = 3.5 \times 2\pi \: r$
$= 3.5 \times 628$
$= 2198m$

$Displacement \: after \: 2m \: 20s \: = 200m$
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$Hope \: my \: ans.'s \: satisfactory.$ !!