Ok here is a question I was working on today but I cannot seem to visualize it properly.

A circular disk of radius r is used in an evaporator and is rotated in a vertical plane. If it is to be partially submerged in the liquid so as to maximize the exposed wetted area of the disk, show that the center of the disk should be positioned at a height r / sqrt(1 + pi^2) above the surface of the liquid.

What is the "wetted" area of the disk? It cannot be the part of the disk that is submerged because then the maximum area would be the entire disk submerged.

Question

Ok here is a question I was working on today but I cannot seem to visualize it properly.

A circular disk of radius r is used in an evaporator and is rotated in a vertical plane. If it is to be partially submerged in the liquid so as to maximize the exposed wetted area of the disk, show that the center of the disk should be positioned at a height r / sqrt(1 + pi^2) above the surface of the liquid.

What is the "wetted" area of the disk?  It cannot be the part of the disk that is submerged because then the maximum area would be the entire disk submerged.

anonymous · Answer

It may just be a poorly worded question...

anonymous · Answer

That's true. I found a solution here ( http://answers.yahoo.com/question/index;_ylt=AjP6YX4F6.ERQSVCCXH8zhHty6IX;_ylv=3?qid=20091128095615AA1AuqI&show=7#profile-info-91HhPVl0aa) but that did not really help much. This particular question was posted in a chapter on integration yet it is an optimization problem. I am not sure how integration can be used here.

anonymous · Answer

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