Question

An athelete completes one round of a circular track of diameter 200m in 40 sec what will be the distance covered and the displacement at the end of 2min 20 sec

Answer 1

D of track = 200 m

Rounds covered in 40 sec = 1

Rounds in 1 second = 1/40

Rounds in 2 min 20 second

${\implies 140 sec = \dfrac{1}{40}\times 140}$

${\implies\dfrac{7}{2}}$

= 3.5  

Distance in one round = C of circular path

${\implies 2\:pie\: r = 2\:pie \dfrac{d}{2}}$

${\implies 2\times\dfrac{22}{7}\times \dfrac{200}{2}}$

${\implies\dfrac{4400}{7}m}$

Distance in 3.5 round

${\implies\dfrac{4400}{7}\times 3.5}$

= 2200m

= 2.2 km

After 3 round displacement = 0

AB = Diameter

= 200 m