Reactions Summary

The video tutorial covers various types of reaction forces, starting with the normal force, which is always perpendicular to the surface. It then explains pinned supports, which have reaction forces in both X and Y directions due to the pin's constraints. Roller supports are discussed next, highlighting that they allow movement in one direction, resulting in a single reaction force. Finally, cantilevered supports are described, showing how they prevent movement and rotation, leading to reaction forces and a reaction moment.

What is the primary characteristic of normal forces?

• They are parallel to the surface.

• They are always perpendicular to the surface.

• They are always horizontal.

• They can be either parallel or perpendicular.

In a pinned support system, what prevents the beam from moving?

• The length of the beam.

• The pins at both ends.

• The friction between the beam and the surface.

• The weight of the beam.

How does a roller support differ from a pinned support?

• It restricts movement in all directions.

• It allows movement in one direction.

• It only supports vertical loads.

• It provides no support at all.

What additional reaction occurs in a cantilevered support due to its inability to rotate?

• A reaction force in the Z direction.

• A reaction moment.

• A reaction force in the Y direction.

• A reaction force in the X direction.

Which type of support allows for a reaction force that can be positive or negative?

• Cantilevered support

• Roller support

• Pinned support

• Normal support