Question

an athlete completes one round of a circular track of diameter 200m in 40s. what will be the distance covered and the displacement at the end of 2minutes 20 s​

Answer 1

Speed = 

Distance = circumference of the track.

Distance = 

Speed =

Speed = 

time = 2 min 20s = 140s

distance = 140*5*π

distance = 700π

One round of the circular track = 200π

So the athlete completes 3.5 rounds.

The distance between the athlete and his starting point along the track is 0.5 rounds, or a semicircle.

The displacement will be the chord connecting the two points.

The chord of a semi circle is the diameter.

Diameter = 200m.

Answer 2

length AB=200m=2R

time taken to complete one round=40 sec

let the starting point be A

in 140 sec or 2 min 20 sec number of rounds completed=14040=3.514040=3.5

distance traveled=3.5 * (2*π π*R)=3.5*2*π π*100 m=2200 m (approx)

displacement refers to change in position from the starting point.the final point is B

as after 3.5 revolutions(starting from A) the athlete will be at B.

displacement=200m