Physics
posted by Mathe on .
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

Use the current and voltage to determine that the resistance is R = V/I = 0.0024 ohms
Then use the resistivity of aluminum (which you will need to look up), together with the resistance R and the length L, to determine the cross sectional area, A.
The volume of the wire is L*A. Multiply that by the density for the mass. 
A=0.00206