The frame shown could be subjected to a variety of forces ap

The frame shown could be subjected to a variety of forces applied at different points. Consider the loads exerted by the pin at A. Which of the following could represent the forces exerted by the pin on the two bars? Forces act in the senses shown.

Solution

The answer is (b).

For the upper beam, the resultant of the two forces will be at 45 degrees to L shape corner , so to counter balance that force, the force by the pin will be upwards in an angle 45 degrees with x axis.

Similarily, for lower beam to keep the beam in horizontal position , force by pin will be as shown in b.