You're taking this diagram too literally.goldfish9776 said:
A pin support, also known as a hinged support, is a type of structural support that allows for rotation and translation of a structure at the point of support.
At a pin support, the reaction forces are typically perpendicular to the surface of the support and can be decomposed into a horizontal and vertical component.
The reaction forces at a pin support can be calculated using the equations of equilibrium, which state that the sum of all forces and moments acting on a structure must be equal to zero.
A pin support allows for both rotation and translation, while a roller support only allows for translation along a single direction. Additionally, a pin support can resist both horizontal and vertical forces, while a roller support can only resist forces in the direction of translation.
The location of a pin support can affect the magnitude and direction of the reaction forces. Placing the pin support closer to a concentrated load will result in a larger reaction force, while placing it further away will result in a smaller reaction force. Additionally, the angle of the reaction force can also be affected by the location of the pin support.
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