A small air compressor operates on a 1.7 hp (horsepower) electric motor for 9.2 hours a day. How much energy is consumed by the motor daily?

Question

 1 hp equals about 750 watts. Answer in units of J.

If electricity costs 25 cents per kilowatt-hour, how much does it cost to run the compressor each day? Answer in units of cents.

Answer 1

Favourite answer

power = 750•1.7 = 1275 watts = 1275 J/s

9.2 hr x 3600 s/hr = 33120 s

1275 J/s x 33120 s = 4.22e7 J

4.22e7 J = 11.73 kW•hr

11.73 kW•hr x 25¢/kW•hr = 293 ¢

Answer 2

total daily energy consumption E = 1.7*0.75*9.2 = 11.73 kwh

daily expenditure = 11.73*25 = 293 cents 

Answer 3

Dimensional analysis problem

1.7hp * 0.750kW/hp *9.2h * 25¢/kWh = 293¢ <<<< 

Answer 4

$2.93 (1.7 x 750 = 1275W) (1275/1000 = 1.275 KW) (1.275 x 9.2 = 11.73 KWH per day) (11.73 x 0.25 = $2.93).