A force (F= (-ky)/√(x^2 + y^2 ) i + kx/√(x^2+y^2 ) j ) N is applied on a block …

Q: A force $ \vec{F}= \frac{-ky}{\sqrt{x^2 + y^2 }} i + \frac{k x}{\sqrt{x^2 + y^2 }}j  $ N is applied on a block, whose position is P (x , y). The block moves on a circular path of radius R. find the work done by the force F in complete rotation.

(a) 2 π Rk

(b) π Rk

(c) 4π Rk

(d) Zero

Ans: (a)