Question

A man running around a circular track of radius 20m covers one complete round in 40s. calculate the distance and displacement covered by him in 3minutes. (please answer with full explanation) very urgent

Answer 1

tatal distance is equal to circumference=2πr
hence total distance covered in first round is 2*22/7*20
by using speed=distance/ time
u can find speed
and then you have to find distance for three minutes
and hence displacement is zero

Answer 2

Distance in circular motion = Circumference of the circle

As we know, circumference of the circle is denoted by


 $2 \pi r$

Distance=


 2 × $\frac{22}{7}$ × 20
 
             = 125.7 metre

This means he completed one round in 40 seconds. Thus, he takes 40 seconds to complete one round


Now for 3 minutes= 180 seconds


now taking the ratio,



[tex] \frac{125.7}{40} = \frac{x}{180} [/tex]




Thus,




                 
$\frac{125.7*180}{40}=x$




Thus

x=565.7


Thus he covered a distance of 565.7 metre in 3 minutes



for displacement let's divide the covered distance by circumference

=565.7/125.7

=4.500


Now converting this in words

this means he has completed 4 rounds and have completed 1/2 round extra, he is on a point parallel to his starting point

thus he is not on his starting position, thus his displacement is not zero. Drawing a line from starting position to his current position, it will pass through the centre, it is the diameter




Displacement= 2×20
                     = 40m


ANS Distance covered in 3 minutes is 565.7 m and displacement is 40m