Answer:
a) [tex]i = 15.033\,A[/tex], b) [tex]\dot E_{in} = 1.804\,kW[/tex], c) [tex]C = 0.496\,USD[/tex]
Explanation:
a) Electric power transmitted into the motor is:
[tex]\dot E _{in} = \frac{(2.20\,hp)\cdot \left(0.746\,\frac{kW}{hp} \right)}{0.91}[/tex]
[tex]\dot E_{in} = 1.804\,kW[/tex]
The current in the motor is:
[tex]i = \frac{1804\,W}{120\,V}[/tex]
[tex]i = 15.033\,A[/tex]
b) The energy delivered to the motor is:
[tex]\dot E_{in} = 1.804\,kW[/tex]
c) The cost of running the motor for 2.50 hours is:
[tex]C = (1.804\,kW)\cdot (2.5\,h)\cdot \left(3600\,\frac{s}{h} \right)\cdot \left(\frac{1}{3600}\,\frac{kWh}{kJ} \right)\cdot \left(0.110\,\frac{USD}{kWh} \right)[/tex]
[tex]C = 0.496\,USD[/tex]
