Friction between the liquid and the pipe wall converts kinetic energy into which form of energy?

Friction between the liquid and the pipe wall converts kinetic energy into which form of energy?

• A. Potential energy
• B. Thermal energy
• C. Chemical energy
• D. Nuclear energy

Answer: (B)

The main idea is viscous friction converting mechanical energy into heat. When liquid flows through a pipe, layers slide past one another and against the pipe walls, encountering resistance due to viscosity. The work done to push the liquid against this friction reduces its kinetic energy and increases the internal energy of the liquid (and the pipe), raising its temperature slightly. That increase in thermal energy is why the correct choice is thermal energy. Potential energy would require height differences, and chemical or nuclear energy come from reactions or nuclear processes, not from ordinary friction in pipe flow.

The main idea is viscous friction converting mechanical energy into heat. When liquid flows through a pipe, layers slide past one another and against the pipe walls, encountering resistance due to viscosity. The work done to push the liquid against this friction reduces its kinetic energy and increases the internal energy of the liquid (and the pipe), raising its temperature slightly. That increase in thermal energy is why the correct choice is thermal energy. Potential energy would require height differences, and chemical or nuclear energy come from reactions or nuclear processes, not from ordinary friction in pipe flow.