A simply supported beam is a structural element that is supported at both ends, allowing it to freely span between the supports. This type of beam can carry loads applied along its length, which causes it to bend. The supports do not provide any moment resistance, meaning the beam can rotate at the ends. In engineering, simply supported beams are commonly used in bridges, buildings, and various constructions due to their simplicity and ease of analysis. They are often analyzed using principles from mechanics to determine how they will behave under different loading conditions, ensuring safety and stability.