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-   -   Funnel vs. Cylinder (http://www.physicsforums.com/showthread.php?t=312552)

Melawrghk May7-09 04:47 PM

Funnel vs. Cylinder
 
1. The problem statement, all variables and given/known data
Pretend you have a container into which you're pouring water. We often use funnels, but why? Like if you have a funnel with the same exit radius as a cylinder, why is using a funnel more efficient?

The area still says the same, so I don't know. Help?

fluidistic May7-09 04:50 PM

Re: Funnel vs. Cylinder
 
Maybe because a funnel won't fall into the recipient you are filling while a cylinder would!

Melawrghk May7-09 04:55 PM

Re: Funnel vs. Cylinder
 
I could glue the cylinder onto the recipient :D

Could it be because pressure changes differently between the two shapes? Cylinder loses the volume of water and height of water linearly. But a even if a cone loses same amount of water by volume, it would be different by height?

fluidistic May7-09 05:05 PM

Re: Funnel vs. Cylinder
 
Quote:

Quote by Melawrghk (Post 2189515)
I could glue the cylinder onto the recipient :D

Could it be because pressure changes differently between the two shapes? Cylinder loses the volume of water and height of water linearly. But a even if a cone loses same amount of water by volume, it would be different by height?

This is right. But why would pressure be a problem? If it is a problem then it explains it all, but if you use it for cooking or things like that I think it's because the funnel simply don't fall into the recipient and also because you don't have to be very precise (accurate) when you pour the water into the funnel since it's almost sure all the water will get on the funnel and not on the floor. While when pouring water in a thin cylinder requires more accuracy from your part and you can't also pour water with it as fast as with a same volume funnel.

Melawrghk May7-09 05:10 PM

Re: Funnel vs. Cylinder
 
Well it's for my project, and I'm supposed to justify use of cone as opposed to having just an open (cylindrical) end. I think I'll be able to develop an argument from this. Thanks tons!

fluidistic May7-09 05:27 PM

Re: Funnel vs. Cylinder
 
Ok good luck then! I'm hoping for someone to point out any other information we might be missing.


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