The correct answer is: A. Two bars
A compound truss is a truss that is made up of two or more simple trusses. The simple trusses are connected by bars, which transfer the loads from one truss to the other. The number of bars required to connect two simple trusses depends on the geometry of the trusses and the loads they are designed to carry.
In the simplest case, two simple trusses can be connected by two bars, one bar connecting the top chords of the trusses and one bar connecting the bottom chords of the trusses. This type of connection is called a simple connection.
If the simple trusses are not aligned, then more bars may be required to connect them. For example, if the simple trusses are at right angles to each other, then four bars will be required to connect them. This type of connection is called a right angle connection.
The bars that connect the simple trusses can be made of a variety of materials, including steel, aluminum, and wood. The size and shape of the bars will depend on the loads they are designed to carry.
Compound trusses are often used in bridges and other structures that require a strong and lightweight framework. They are also used in machines and other devices where a rigid structure is required.
Here are some brief explanations of each option:
- Option A: Two bars. This is the correct answer. Two bars are required to connect two simple trusses in the simplest case.
- Option B: Three bars. Three bars may be required to connect two simple trusses if the simple trusses are not aligned.
- Option C: Three parallel bars. Three parallel bars cannot be used to connect two simple trusses.
- Option D: Three bars intersecting at a point. Three bars intersecting at a point cannot be used to connect two simple trusses.