01
Front
What does a free-body diagram represent?
Back
A free-body diagram isolates one selected body and shows the external forces and moments acting on it.
Free Online Flashcard Deck
5 Rigid-Body Equilibrium and Free-Body Diagrams Free Online FlashCards
Study 5 Rigid-Body Equilibrium and Free-Body Diagrams with 12 free online flashcards. Review key terms, definitions, and concepts with this interactive flashcard deck.
12 cards
02
Front
What reaction does an ideal cable exert?
Back
An ideal cable exerts one tension force along the cable, pulling away from the body.
03
Front
What three equations describe planar rigid-body equilibrium?
Back
The net horizontal force, net vertical force, and net moment must each be zero: ∑Fx=0, ∑Fy=0, and ∑MO=0.
04
Front
When does a force have zero moment about a point?
Back
A force produces zero moment about a point when its line of action passes through that point.
05
Front
Why take moments about A in the beam example?
Back
Taking moments about A eliminates both pin reactions because their lines of action pass through A.
06
Front
What if a structure has more unknown reactions than equilibrium equations?
Back
If there are more unknown reactions than independent equilibrium equations, statics alone generally cannot solve the system; additional information such as deformation or compatibility is needed.
07
Front
What key information belongs on a free-body diagram?
Back
Show all applied loads, the body's weight when relevant, support reactions, dimensions, and a clear coordinate system.
08
Front
How are internal forces treated on an assembly’s free-body diagram?
Back
Internal forces between parts of the selected assembly do not appear on its overall diagram. If one part is isolated, forces from the other parts become external to it.
09
Front
What reaction does a smooth surface or roller exert?
Back
A smooth surface or roller exerts one reaction force normal to the surface.
10
Front
What reactions does an ideal pin or hinge provide?
Back
A pin or hinge provides two force components, usually horizontal and vertical, but no reaction couple.
11
Front
What reactions does an ideal fixed support provide?
Back
A fixed support provides two force components and a reaction couple.
12
Front
What is a common sign convention for planar moments?
Back
A common convention takes counterclockwise moments as positive and clockwise moments as negative.