Question

a particle is moving in a circle of radius 5m. calculate the distance covered and displacement when it completes 3 revolutions.

Answer 1

radius is 5 cm. so circumference of circle = 31.4 cm. So distance = 3 × 31.4 = 94.2
displacement will be zero because initial and final point is same

Answer 2

GIVEN :

The Radius of the circular path = 5 m

TO FIND :

Distance travelled after 3 revolutions by the object

Displacement of the object.

SOLUTION :

In a circular path the distance is equal to the circumference of the circle. Hence,

$Distance = 2\pi r \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 2 \times 3.14 \times 5 \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = 31.4 \: m$

1 revolution of the circle, distance = 31.4 m

(i) 3 revolution the distance = 3×31.4 = 94.2 m

(ii) Displacement =0. As the object moves from the same point and reaches to the same point.