Question

# A particle moves in a circular path of radius r. In half the period of revolution its displacement and distance covered are.\begin{align} & \text{A}\text{. }2r,\pi r \\ & \text{B}\text{. }r,\pi r \\ & \text{C}.\text{ }2r,2\pi r \\ & \text{D}\text{. }r\sqrt{2},\pi r \\ \end{align}

Hint: We know that basically in circular motion the total displacement for half complete motion is the shortest distance between initial and final points that is diameter. And the distance covered is actual path travelled that is half the circumference.

The displacement of a particle for complete one revolution will be its diameter.
Hence displacement will be 2r where,
R is the radius of the circle.
The distance travelled by the particle for complete half revolution will be half the circumference.
Hence distance travelled will be $\pi r$.

So, the correct answer is “Option A”.