[psyl0cibe]

A copper refinery produces a copper ingot weight 130. lb. If the copper is drawn into wire whose diameter is 8.45mm how many feet of copper can be obtained from the ingot? The density of copper is 8.94 g/cm³

I've been working on this problem for at least an hour and all the answer I've come up with are wrong.
I've been using the formula density=mass/volume
So, I end up with 8.94g/L = 130 lb/8.45mm x(?)
Converting 130 lb to grams gives me 58,900. In my class we don't have to be specific because we use scientific notation for the conversions and such. Then converting 8.45mm to cm I got 0.845 cm. I'll show the list of answers I've ended up with using this and another formula.
256 ft, 2.89 ft, .275 ft, 1170 ft, 6.20 ft., 3.86 ft. .356 ft, .004 ft, 34.2 ft.
I was just wondering if any of you know how to set up the problem correctly so I can get the correct answer. Thanks for any help.

[xiankai]

1.19g/L

i didnt know that 8.94 can be converted into 1.19 with by a factor of 10^3.

8.45mm x(?)

area of cylinder = pi x r x r x h

-edit- replaced cone with cylinder, my mistake, sorry  

[psyl0cibe]

used the area of a cone in the formula and ended up with 11,800 which was incorrect, i even did the square root of that and square root again and it was still wrong. Can someone show me how the formula should be set up

[Borek]

What area of cone has to do with the problem?

To calculate mass of wire you need its volume. Wire is basically a cylinder. Cylinder volume is ?r²x, where x is the length you are looking for.

[jdurg]

Okay, the first thing you need to do is get the correct density.  The density of copper is 8.94 g/mL and NOT 8.94 grams per Liter.    The mass of the wire is 59,020 grams.  With the mass and density known, you can now calculate the volume of the copper that you have.

59,020g / 8.94g/mL = 6601.79 mL of copper.

Now we know that the wire has a diameter of 0.845 centimeters and a wire is basically a cylinder, so the volume is equal to pi*r*r*h where h would be the length of the wire.  

We have the value of pi, we have the diameter, and we have the volume so calculating h should be easy.

6601.79 mL = pi*0.4225*0.4225*h.

h = 11772 centimeters.  

there are about 2.54 centimeters in an inch, so your wire is about 386 feet long.

[DrCMS]

1) Convert the 130lb to grams.
2) Convert that into a volume using the density given.
3) Divide by the cross sectional area of the wire in cm.
4) Convert this length in cm to feet.

[Borek]

there are about 2.54 centimeters in an inch, so your wire is about 386 feet long.

 

[jdurg]

What's so funny?  

[Borek]

Perhaps that's more funny for someone using metric system (fact that there are dozen inches in a feet is not so obvious here), but

"there are about 30.5 centimeters in in a feet, so your wire is about 386 feet long"

sounds much more logical

[jdurg]

Ahhhhh.  Okay.  Now I understand.