Question

What is the distance travelled by a body and its displacement when it completes one revolution around a circular track with radius $r$?

• A. Distance and displacement are both same and equal to 0
• B. Distance and displacement are both same and equal to 2πr
• C. Distance = 0 and displacement = 2πr
• D. Distance = 2πr and displacement = 0

Answer 1

The correct option is D

Distance = 2πr and displacement = 0

Distance is a scalar quantity and it only depends on the magnitude and is equal to the total path covered.
Here, distance $=$ perimeter of the circular track $=2\pi r$
Displacement is a vector quantity and it depends on magnitude and direction, it depends only on the initial and final positions of the body and when you join initial and final points with a straight line, it gives the displacement of the body. Here, the initial and final positions are the same, hence, displacement is zero.