How to derive First moment of area for composite beam?

Answer 1

To derive the first moment of area (Q) for a composite beam, first identify the individual components of the beam and their respective areas (A). Calculate the distance from a reference axis (usually the neutral axis) to the centroid of each component (ȳ). The first moment of area for each component is then calculated using the formula ( Q = A \cdot \bar{y} ), where ( \bar{y} ) is the distance from the centroid of the component to the reference axis. Finally, sum the first moments of all components to obtain the total first moment of area for the composite beam.