Q5. A child completes one round of a circular park of diameter 50 m in 20 s. what will be the distance covered and displacement at the end of 1minute 10 seconds?
Answers
Displacement is the shortest distance possible between initial and final position.
As the athlete is in circular motion , displacement is zero. [ THis is because , the initial and final position is the same ]
Distance covered in 1 round = Circumference of the circle
Circumference of the circle = 2πr
Diameter = 200 m
Radius = 100 m
Distance covered in 1 round[ 40 sec ] = 2 × 22/7 × 100 = 628.57 m
Distance covered in 1 sec = 628.57 ÷ 40 = 15.71 m
2min 20 sec = 140 sec
Distance covered in 140 sec = 15.71 × 140 = 2199.4 m
Answer:
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=[math]\frac{140}{40} = 3.5[/math]
distance traveled=3.5 * (2*[math]\pi[/math]*R)=3.5*2*[math]\pi[/math]*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