Question

A built-in-end cantilever support is replaced with what reaction force(s) when a free body diagram is being drawn.
A.) A reaction force in the X axis
B.) A moment force
C.) All of these
D.) None of these
E.) A reaction force in the Y axis

Option B and E

A moment force

Reaction in the Y axis

Explanation:

A built-in-end cantilever support is one which has one end fixed into a wall. This makes it rigid and immovable in the x direction.

Cantilevers are usually loaded in the y-direction, and this usually sets up the following:

1. Rotation reactions: This is because the load is applied a distance away from the support, in a direction that is perpendicular to the length of the beam. This sets up a rotational force on the beam. and consequently, a rotational reaction at the support ( A moment force)

2. Reaction forces in the Y axis: The mere fact that it is usually loaded in the y – axis, by Newton’s third law, there will always be reaction forces set up in the y- direction at the support.

Note: No reactions in the x axis are set up here, because loading on built-in-end cantilever support is usually vertical.

Hence, option B and E are correct.