Present in a complex form (general and exponential form), and draw in a complex plane the voltage, as well as the vector -phasor of the voltage, whose current value is u (t) = 212.13 ∙ sin (ω ∙ t - 63˚) v

In the winter, in order to keep the classroom steadily at 68 f before 10 pm, heating with an average rate of 42,000 btu/hr is provided. assume the outdoor temperature maintains at 32°f, determine the electrical power (kw) required to (a) operate a reversible heat pump (b) operate a real heat pump with a cop (7) of 4.5 and (c) operate an electrical-resistance heater.