# Simple Unit Analysis

1. Mar 1, 2014

### ainster31

1. The problem statement, all variables and given/known data

$$Let\quad n\quad =\quad the\quad number\quad of\quad hours\quad I\quad run\quad a\quad 40\quad kilowatt\quad generator.\\ Assume\quad that\quad it\quad costs\quad 0.08\quad for\quad 1\quad kWh.\\ Revenue\quad from\quad generator=\frac { 0.08 }{ kW\cdot hours } \quad (40\quad kW)\quad (n\quad hours)\\ =3.2n\\ \\ Suppose\quad I\quad want\quad to\quad make\quad 6.40\quad from\quad the\quad generator.\\ 6.4=3.2n\\ n=2$$

2. Relevant equations

3. The attempt at a solution

What am I doing wrong? Why isn't n in hours?

2. Mar 1, 2014

### Dick

Because when you write time=n*hours, the units are in the "hours" part and n itself is dimensionless. If you the units to be included in 'n' just write time=n.

3. Mar 1, 2014

### ainster31

Ah, got it. Thanks.