question_answer

In the figure shown, a cubical block is held stationary against a rough wall by applying force 'F, then incorrect statement among the following is

A) frictional force f = mg

B) F = N, N is normal reaction

C)  F does not apply any torque

D) N does not apply any torque

Correct Answer: D

Solution :

For equilibrium, f = Mg F = N For rotational equilibrium normal will shift downward. Hence torque due to friction about centre of mass = Torque due to normal reaction about centre of mass.