A rod of mass `m` is supported by string `AB` and friction due to wall. Then friction force on rod due to wall is `:`
`(g=` acceleration due to gravity `)`

Options

A. `mg` upward
B. `mg`downward
C. `(mg)/(2)` upward
D. Data insuffient

Answer

C

Explanation

Torque about `A`
`mg.(l)/(2)-fl=0`
`F=(mg)/(2)`