Question

answer 1 no. question

Answer 1

Hello friend,
r=100m
time to cover 1 round of the circle=40sec
circumference=2Πr=2×22/7×100=4400/7m
speed=(4400/7)/40=110/7mps
t=2min20sec=140sec
distance covered=speed×time=(110/7)×140=2200m=2.2km
displacement:-
After every 40sec displacement is 0m.
and also after every 20sec later from when displacement is 0m at that time displacement is 2r=200m
Here,
t=140sec
So,140-40=100
100-40=60
60-40=20sec
So, at 20sec the person is 200m far from the origin I.e. displacement=200m
hope it helps.

Answer 2

diameter=200 m
so radius r =100
hence length of track =2πr=2π*100=200π
velocity of the athlete is 200π/40 (m/s)
                                      =5π
after each 40 sec athlete complete one round of the track so in 2min 20s athlete complete 140*5π distance =2193.1148 or 700π.this is the amount of distance covered.the angle covered for final position is( 2π/200π)*700π
                                                                                      =7π
i.e.( 2+2+2)π+π so the dis placement from the initial to final position is the length of diameter i.e. 200 m.this is because π angle means half circle.