Share Your Handy Formulas

[LeChatNoir]

So the other thread I started tonight got me thinking about handy, simple formulas and conversion tidbits I'd picked up over the years. I thought it might be fun and good to share some of these and ask anyone else with such things to do the same. So here's what I've got at the moment:

Weights

Steel: 0.283 lbs/in3
Aluminum: 0.098 lbs/in3

Now you can figure the weight of any piece of steel or aluminum by multipling the cross-sectional area by the length.

i.e.: a piece of 1/2" square mild steel 36" long would weigh:

(.5*.5*36)*.283=2.547lbs

Punching holes in Mild Steel:

Diameter x thickness x 80 = tons required to punch hole

Punching polygons in Mild Steel:

Perimeter x thickness x 80 = tons required to punch shape

For brass, replace 80 with 65

[Zhust]

Electricity, at US$0.114/KWH (fairly close to many utility costs) means that 1 watt will cost you 1 dollar to run 24 hours a day for a whole year. 100 watts = $100/year, for instance.

Gasoline: 1 mile-per-gallon is 500 hogshead-per-furlong.

Which is less useful?

[phil]

1 gallon of water equals 8.33 lbs.
1 gallon of gasoline equals 5.8 to 6.5 lbs.
1 gallon of ethanol equals 6.59 lbs.

If you are thinking, for example, of filling a 55 gallon drum with water, multiply 55 X 8.22 lbs, then look at your owners manual for your vehicle and see what the gross vehicle load limit is. Also consider how you are going to pick the container up and move it where you need it and how you are going to get the water out.

If you are bringing lots of liquor or extra gasoline, check those weights, too.