The work done an a particle of mass `m` by a force
`K[(x)/((x^(2) + y^(2))^(3//2)) hati +(y)/((x^(2) + y^(2^(3//2))) hatj)]`
(K being a constant of appropriate dimensions), when the partical is taken from the point (a,0) to the point (0,a) along a circular path of radius a about the origin in x - y plane is

Options

A. zero
B. `(kpi)/(2a)`
C. `(kpi)/(4a)`
D. none

Answer

B

Explanation

This force is tangential and constant magnitude done will be product of force and distance.