True or False: Loss of mechanical energy occurs when liquid flows through fittings (e.g. valves, elbows and orifices), pipes entrances and exits, as well as the pipe itself.

• A. False
• B. True
• C. Not enough information
• D. Sometimes

Answer: (B)

Energy is dissipated as liquid moves through real piping components. When fluid flows through fittings such as valves, elbows, or orifices, as well as through entrances, exits, and along the pipe length itself, friction and turbulence convert some of the mechanical energy (pressure plus kinetic energy) into heat. This shows up as head losses in the energy balance (Bernoulli equation with a loss term): h_L includes friction losses along the pipe and minor losses at fittings and entrances/exits. As flow continues, the mechanical energy head declines because energy is being irreversibly dissipated. So the statement is true—the flow experiences energy losses in those regions. The exact amount depends on flow rate and the geometry/roughness of the components, but the phenomenon itself is real and expected.