A U - shaped smooth wire has a semicircular bending between A and B as shown in the figure. A bead of mass m moving with uniform speed v through the wire enters the semicircular bend at A and leaves at B. the average force, exerted by the bead on the part AB of the wire is:

Options

A. 0
B. `(mv^(2))/(pid)`
C. `(2mv^(2))/(pid)`
D. `(mv^(2))/(pid)`

Answer

B