A fixed `U`-shaped smooth wire has a semi-circular bending between `A` and `B` as shown in the figur
Channel: Doubtnut
Date: 2020-01-26

A fixed `U`-shaped smooth wire has a semi-circular 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 magnitude of average force exerted by the bead on the part `AB` of the wire is