# A small air compressor operates on a 1.6 hp (horsepower) electric motor for 5.6 hours a day.?

1. A small air compressor operates on a 1.6 hp (horsepower) electric motor for 5.6 hours a day. How much energy is consumed by the motor daily? 1 hp equals about 750 watts. Answer in units of J.

2. If electricity costs 17 cents per kilowatt-hour, how much does it cost to run the compressor each day? Answer in units of cents

### 1 Answer

- qrkLv 72 months agoFavorite Answer
In reality, this question is unanswerable since the power consumption of the motor isn't given.

The specifications show the rating of the motor. In operation, the motor will output less than the specified rating. Also, efficiency is a factor which is not given. Also, the startup current will be high and the power needed will change depending on the tank pressure. You can see why this question is bogus.

Since this is a homework problem, you'll assume that the motor output is 1.6 HP and you have 100% efficiency.

Thus, 1.6 HP * 750 W/HP * 5.6 hr = 6720 W*hr = 6.720 kW*hr

1 Joule = 1 Watt*second. From this you can figure out the answer. You'll need to convert from hours to seconds. This problem is all about learning to deal with units conversion.