Observe the situation depicted in the figure. The wall is smooth, whereas the contact surfaces between A and B are rough. In equilibrium, the friction exerted on B by A

Step-by-step solution

Consider the system comprising both blocks A and B. The external forces acting on this system in the vertical direction are their respective weights, m_A g and m_B g , which act downwards. Since the wall is smooth, it cannot exert any vertical frictional force on block A. It only provides a horizontal normal reaction. The applied force F is purely horizontal and provides no vertical component. Therefore, there is no external upward force to balance the total downward gravitational force (m_A + m_B)g . Since the net