Engineering Statics by Hand: Force Vectors, Moments, Free-Body Equilibrium, Support Reactions, Trusses by Joints and Sections, Centroids, Second Moments of Area & Friction

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Resolve four cable forces on a lifting ring into x and y components, add them into a resultant, compute its magnitude and find its direction with ATAN and a quadrant correction.
• Compute the moment of four forces about the base point O of a sign gantry, add a couple, move the resultant to a second point and locate its line of action.
• Set up ΣFx = 0 and ΣFy = 0 for a ring held by two cables and a guide line, solve the 2 × 2 system with Cramer's rule written out and compare the tensions with a fictional rating.
• Set up the free-body equations of an L-frame bracket on a pin and an inclined roller, solve the moment equation first, get the pin reactions from the force sums and check that every sum is zero.
• Compute member angles from joint coordinates, solve a roof truss joint by joint – A first, then B – and read which members are in tension, in compression or carry no force.
• Cut a toy footbridge truss through three members, find each force with one equation, compare the results with a joint-by-joint table and name the most loaded member.
• Locate the centroids of a T-section with a slot and of a U-channel with SUMPRODUCT and compute their second moments of area about the horizontal centroidal axis with the parallel-axis theorem.
• Compare the push that makes a crate slide with the push that tips it, then check three load cases on the footbridge truss: the largest member force per case, its use of a fictional allowable force and a chart.