# Homework Help: Using Volume of a cylinder and Density of copper, find the amount in meters to fill

1. Sep 18, 2009

### geoti8

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

copper can be drawn into wires. how many meters of 34-gauge wire (diameter 6.304 x 10 -3 in) can be produced in copper from 8.60 pounds of covelite, an ore that is 60% copper by mass. (hint: treat the volume as a cylinder, V of cylinder= pie r squared, density of copper = 8.95 g/cm3

2. Relevant equations

V of cylinder = pie r (squared)

3. The attempt at a solution

I dont know where to start, is the 60% mass of the covelite ther to confuse me? or is it relevant?

2. Sep 18, 2009

### rock.freak667

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

if there are 8.60 lbs of covelite and 60% of this is copper, how many lbs if copper is in it?

Now that you have the mass, what is the volume, given the density and the found mass? (Note that your mass should be in grams)

also I think your equation should be V= πr2h, as πr2 alone gives units of m2 which is used for area. (h=height of the cylinder)

3. Sep 18, 2009

### geoti8

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

ok..I'm following you up until then.. does that mean that for the 34-gauge wire i use the 6.304 x10^-3 and thats the diameter? so for the (vol = pie r^2) i would use (6.304x10^-3 / 2) for the radius?

so I used the V = m/d formula and got 255.66...what do i do with that now?

i'm thinking myself to death here. should have never take 5 years off school to go to the military.

4. Sep 18, 2009

### geoti8

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

ok, πr2 alone gives units of m2 ...does that mean that i just take the square root of my m2? because i'm looking for length in meters?

5. Sep 19, 2009

### rock.freak667

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

worry not! We will get through here.

Right now, so you have V=255.66 cm3 (assuming you converted your lbs to grams)

so now you know that V=πr2h. (r is half your diameter, so convert that to cm!)

so put πr2h=255.66 and solve for h

6. Sep 19, 2009

### geoti8

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

ok so i plug my vol, and radius into the equation:

255.66 = pi (6.304x10^-3 /2)^2 x h ........ and get...

255.66h = (3.14)(.003152)^2 ...

h = .000031196/255.66 ...

1.22 x 10^-7 is my m2? (was that in cm? or m?) do i need to get the square root...

3.493 x 10^-4 is that in cm or meters ??

7. Sep 19, 2009

### rock.freak667

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

convert the 6.304x10^-3 inches into cm, then plug it into the equation

8. Sep 19, 2009

### geoti8

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

ok so apparently the answer was 1.88 x 10^12 or ^14

and i got

1.875 x 10^14 or ^12

as soon as i saw i got it incorrect i stopped caring, FML.

9. Sep 19, 2009

### geoti8

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

thanks for your help though, you must be a teacher, professor..or something along those lines to give me step by step help like that

10. Sep 19, 2009

### rock.freak667

Re: using Volume of a cylinder and Density of copper, find the amount in meters to fi

1.875 ≈ 1.88 how'd you get it wrong?

(also, I am a student like you )