Question

A particle is moving in a circular path of radius r, the displacement and distance after covering half a circle would be:

• A. $Zero,\pi r$
• B. $2r,\pi r$
• C. $2r,Zero$
• D. $\pi r,Zero$

Answer 1

The correct option is B $2r,\pi r$

Given, radius of the circle is '$r$'.

Circumference of circle $=2\pi r$
Distance travelled after half a circle
$=\frac{2\pi r}{2}=\pi r$

But displacement is the shortest path between the final position and initial position.
In this case, it is the diameter, which is $2r$.