2.2. Three-force members

Try these first

1. 1.

   Define a three-force member.

   Hint

   Focus on the number of forces and their action.

2. 2.

   What two conditions must be met for a three-force member?

   Hint

   Think about how forces interact in a flat space.

3. 3.

   What defines a three-force member?

   • Two forces acting
   • Three forces in the same plane
   • Four forces acting at random angles

   Hint

   Think of the member's stability.

4. 4.

   Is a three-force member in static equilibrium if forces act at non-concurrent angles?

   • True
   • False

   Hint

   Review the definitions of force interaction.

5. 5.

   A three-force member has forces of 30N, 40N at angles of 30 and 45 degrees, calculate the resultant force and determine static equilibrium.

   Hint

   Resolve forces to their components.

6. 6.

   Given a truss structure with a three-force member subject to unknown applied forces, write the equations necessary to solve for these forces.

   Hint

   Consider the geometry of the structure.