Q1: Energy equation is usually applicable to

ANS:D - steady flow.

The energy equation is typically applicable to steady flow conditions. The energy equation, also known as the Bernoulli's equation, is a fundamental principle in fluid mechanics that describes the conservation of energy along a streamline in steady, incompressible flow. It states that the total mechanical energy per unit mass of a fluid particle remains constant along a streamline, neglecting losses such as friction and heat transfer. In steady flow, the flow parameters such as velocity, pressure, and elevation do not change with time at any point in the flow field. This allows the application of the energy equation to analyze and predict the behavior of fluid flow in various engineering and fluid mechanics applications. While the energy equation can be applied to both laminar and turbulent flow regimes, it is most commonly used in the analysis of steady flow situations where the flow parameters remain constant over time. Therefore, the energy equation is usually applicable to steady flow conditions.