# Conceptual question regarding equal and opposite reactions

## Main Question or Discussion Point

Suppose you have a can (like a spray can) in a vacuum. You poke a hole in the can and the pressure from the can pushes it to the right. Now suppose you have a vacuumed can within a pressurized container and then you poke a hole in it. Which way (if at all) does it move?

I know this is sorta like the Feynman sprinkler problem, and because of this (I guess) similar analog I keep thinking that it wont go anywhere. Is this correct?

I dont think it will go anwhere. I actually poked a hole in a water bottle and submerged it in my sink to prove it to myself. It didn't go anywhere, but I cant explain it using Newton's laws. Any help?

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Hi mateomy, :)

Here's how I believe it works.

Initially the vacuum can will have the same pressure on all sides.
When you poke a hole in one side, you effectively reduce the pressure on that side.
So the can will move towards the hole.

With an empty water bottle in a sink the force will be rather small.
But then, if you have a full water bottle and put it a table, I don't think it will move (much) when you unplug it.