Engineering Board Exam Reviewer · Engineering Mechanics · medium

Internal forces within a member are generally NOT shown in the free-body diagram of the whole structure because:

1. Internal forces are always equal to zero
2. Internal forces cannot be calculated
3. Internal forces only exist in flexible bodies
4. The FBD is meant to show only external forces acting on the isolated body

Answer

D. The FBD is meant to show only external forces acting on the isolated body

Solution

An FBD isolates the entire body or system, so internal forces between parts of that same body cancel out internally and are not shown.

More Engineering Mechanics questions

1. For a ladder leaning against a smooth (frictionless) wall and resting on a rough floor, the free-body diagram of the ladder should include:
2. In a free-body diagram, the weight of an object is typically represented as a force acting:
3. When drawing an FBD of a two-body system where Body A rests on Body B, the contact force that Body B exerts on Body A should be:
4. A fixed (built-in) support in a free-body diagram provides:
5. A roller support in a free-body diagram provides a reaction:
6. A pin (hinge) support in a free-body diagram provides reaction force(s) in:
7. A free-body diagram (FBD) of an object should show:
8. Newton's third law, as applied in statics, states that:
9. Two equal, opposite, and parallel forces that do not share the same line of action produce:
10. A load applied over a very small area, idealized as acting at a single point, is called a:

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