Statics: free-body diagrams and equilibrium

What you’ll practice

Build clean free-body diagrams (FBDs) and translate them into correct equilibrium equations for 2D and 3D statics. The focus is on identifying all external forces, moments, and constraints before you start solving.

Each question is multiple-choice with 4 options and no timer, so you can reason carefully and check your sign conventions. Choose your preferred question count and difficulty before you start to match your study time and confidence level.

Common pitfalls to avoid

Most mistakes come from missing reaction components, mixing up action–reaction pairs, or placing forces on the wrong body. Watch for distributed loads, equivalent resultants, and the difference between internal member forces and external loads.

How difficulty is balanced

The quiz mixes quick concept checks with longer multi-step setups, so you get both speed practice and deeper problem solving. Easier items reinforce core rules (ΣF=0, ΣM=0), while harder ones add combined loading, multiple supports, or tricky geometry.

Tips for better scores

• Isolate one body at a time; redraw the FBD even if a diagram is provided
• Label axes and positive moment direction before writing equations
• Replace distributed loads with an equivalent resultant at the correct location
• Confirm support models (pin, roller, fixed) and include the right reaction components
• Use ΣM about a point that eliminates unknown reactions whenever possible
• Sanity-check units and directions; a negative result often signals a reversed assumption