A weightless rod is acted on by upward parallel forces of `2 N` and `4N` ends `A` and `B` respectively. The total leng th of the rod `AB=3m`. To keep the rod in equilibrium a fo rce of `6 N` should act in the following manner :

Options

A. downward at any point between A and B
B. downward at the midpoint of AB
C. downward at a point C such that AC=1 m
D. downward at a point D such that BD=1m

Answer

D

Explanation

for equilibrium net torque at B end =0
`-2(3)+6xx x=0,x=1`m