1. The problem statement, all variables and given/known data A cylindrical wire of radius 3mm has current density, J=3s |φ-[tex]\pi[/tex]| z_hat. Find the total current in the wire. 2. Relevant equations 3. The attempt at a solution I believe all I have to do is integrate over the area, but for some reason I can't get it to work. Is the differential area going to be da=s ds dφ? In that case s goes from 0 to 3mm and φ goes from 0 to 2Pi? The 'z' direction is throwing me off a bit. Thanks.