*A particle is moving along a circular path of radius 5m and with uniform speed 5 m/s. What will be the average acceleration when the particle completes half revolution?*

(A) zero

(B) 10 m/s^{2}

(C) 10 π m/s^{2}

(D) 10/π* m/s ^{2}*

** Solution :** The change in velocity when the particle completes half revolution is given by

Dv = 5 m/s – (-5 m/s) = 10 m/s

Time taken to complete half revolution

t = π r/v = π×5/5 = π

Average acceleration = Δv/Δt =10/π m/s

^{2}