## Wednesday, June 13, 2012

### How many blades of grass do I own?

While mowing the grass the other day, I began thinking about and estimating the number of blades of grass I own. While most of this grass is crab grass, I'll attempt a loose estimation anyway, using unit conversion techniques.  First, a few assumptions.

• My yard is roughly rectangular, approximately 200 feet long and 80 feet wide.
• A square inch of grass contains on average 100 blades of grass
The area calculation is simple enough, 200 * 80 = 16000 square feet. Converting to square inches requires a multiplication of 12*12 or 144 square inches per square foot.  Altogether then:
$\frac {200ft\cdot80ft}{ } \frac{144 in^{2}}{ft^2} \frac{100 grass}{in^2} = 203,400,000$

Being rather resentful of this grass that continues to require cutting, I also calculated how many grasses get severed per second, knowing that it takes me approximately 75 minutes to mow:
$\frac {203,400,000 blades}{75 min } \frac{1 min}{60 sec} = 45,200 \tfrac{blades}{sec}$

#### 1 comment:

1. Hi Rocky. You can check my math. I calculate that with a 20" mower and no overlap, you will need to mow at an average speed of 27.54 in/sec.