Unit Summary: Students will learn how to identify and calculate forces acting on a body when it is in static equilibrium. Students will also calculate internal and external forces of a truss.

 Big Ideas:

• Laws of motion describe the interaction of forces acting on a body. 2. Structural member properties including centroid location, moment of inertia, and modulus of elasticity are important considerations for structure design.

• Static equilibrium occurs when the sum of all forces acting on a body are equal to zero.

• Applied forces are vector quantities with a defined magnitude, direction, and sense, and can be broken into vector components.

• Forces acting at a distance from an axis or point attempt or cause an object to rotate.

• In a statically determinate truss, translational and rotational equilibrium equations can be used to calculate external and internal forces.

• Free body diagrams are used to illustrate and calculate forces acting upon a given body.

Essential Questions:

• Why is it crucial for designers and engineers to construct accurate free body diagrams of the parts and structures that they design?

• Why must designers and engineers calculate forces acting on bodies and structures?  

• When solving truss forces, why is it important to know that the structure is statically determinate?

Priority TEKS

• Differentiate between scalar and vector quantities. 

• Identify magnitude, direction, and sense of a vector. 

• Know beam deflection is related to cross sectional geometry and material properties. 

• Know the moment of inertia is related to cross sectional geometry.

• Know the modulus of elasticity defines the stiffness of an object related to material and chemical properties. 

• Know the forces acting on an object are in equilibrium.

• Understand how Newton’s Laws are applied to determine the forces acting on an object.

• Create free body diagrams of objects, identifying all forces acting on the object.

• Mathematically locate the centroid of structural members.

• Calculate the area moment of inertia of structural members.

• Calculate the deflection of a center-loaded beam from the beam’s geometry and material properties.

• Calculate the x- and y-components of a given vector.

• Calculate moments or torques given a force and a point of application relative to a specified axis.

• Use equations of equilibrium to calculate unknown external forces on a truss.

• Use the method of joints to calculate tension and compression forces in the members of a statically determinate truss.

Activities & Projects

• Intro to Statics Guided Notes  

• Centroids Lab 

• Beam Design Guided Notes 

• Beam Deflection Lab 

• Free body diagrams 

• Calculating moments activity   

• Truss Forces Guided Notes 

• Calculating truss Forces HW 

• Truss Statics design Project 

• Assessment