Flux Calculations for Open and Closed Cylinders?

[quaker]

I have a quick question about the wording of a problem I have. It's in two parts.

The first part asks me to find the flux of a given vector field through the closed cylinder of given dimensions. That's fine, no problem.

The second part then asks me to find the flux of the same field through the curved sides of the open cylinder in the previous part.


Is this just poor wording, or is there actually a difference that I am not seeing?

Thanks for your help!

 

[StatusX]

I'm guessing the closed one has caps on it (ie, it includes the disk at each end of the cylinder) and the open one one doesn't. "Open" and "closed" have precise topological meanings, but no surface can be open in R^3, so this can't be what they mean.