¿Cómo se explica que un país necesite importar electricidad y a la vez pueda exportarla?

Why there is no inductive reactance in dc circuits

Oxygen undergoes an isentropic expansion from 120 degree c and 280 kpa absolute to 140 kpa absolute. determine the final temperature of the oxygen and the amount of work per kg of o_2 produced in the process if it is adiabatic.

Dao makes a table to identify the variables used in the equations for centripetal acceleration. what quantities belong in cells x and y?