This type of coma is usually reversible once the blood sugar is corrected. Oxygen deprivation: Oxygen is essential for brain function. Cardiac arrest causes a sudden cutoff of blood flow and oxygen to the brain, called hypoxia or anoxia.
The external power supply is the AC power adapter that converts household AC electricity voltages to the much lower DC voltages needed to charge a mobile phone's internal battery.
External forces are also known as nonconservative forces. Kinetic energy is the energy caused by the movement of the system, and potential energy is the energy the system can use. The total energy of the system is the sum of the two.