The arm can rotate freely about the pin Additional loads act

The arm can rotate freely about the pin. Additional loads act on the arm. Could the reaction of the pin on the arm be as shown? I is possible. II is possible I is possible. II is impossible I is impossible. II is possible I is impossible. II is impossible Cannot say without more information

Solution

1 is imposible and 2 is possible.

reason: pin joint is equivalent to hinge joint. pin joint cannot constrain moment it constrains only vertical and axial loads. these are the only reactions it can exert or withstand.

think it like your door hinge. when you apply a force on the door it will rotate about hinge point but hinge point will not move either in any coordinate.

depending on the magnitudes, the resultant can be in the given direction.