# Aluminum wire, current, voltage, density, find mass

1. Mar 9, 2005

### vaxopy

An aluminum wire is hung between two towers and has a length of 175 m. A current of 125 A exists in the wire, and the potential difference between the ends of the wire is 0.300 V. The density of aluminum is 2700 kg/m3. Find the mass of the wire

I have no idea how to do this :'(

2. Mar 9, 2005

### dextercioby

HINT:
$$R = resistivity \ \frac{l}{S}$$

Daniel.

3. Mar 9, 2005

### Gamma

Resistance $$R = s \frac {l}{A}$$ where s is the resistivity of Aluminum. Find the cross sectional area A using this equation. (R is found using ohm's law V = I*R)

Well, knowing cross sectional area, length and density you can find the
Mass.

4. Mar 9, 2005

### Gamma

Sorry Daniel. I did not see your post. I was busy typing...

5. Mar 9, 2005

### dextercioby

Why do you appologize...?

Daniel.

6. Mar 9, 2005