B If this hand water pump was instead at the bottom of a well...

RipleyGallegos

Summary
If the hand pump was instead placed at the bottom of the well would it require more force on the lever to pump this water up? It seems that it would because of the more water being weighed down onto the piston of the pump.

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phinds

Gold Member
Seems to me what matters is the force required to get the water up and I don't see why that would be any different whether you were pulling it up or pushing it up. The height of the water column is the same either way.

RipleyGallegos

Seems to me what matters is the force required to get the water up and I don't see why that would be any different whether you were pulling it up or pushing it up. The height of the water column is the same either way.
Okay Thank you! What if the little lever only pumped 1 gallon per stroke at like only 10lbs of pressure. & say his was a well with 500 gallons in it. From the top it seems there isn't much of any water weighing down on the piston so that the lever is very easy to push n pull.
If the piston is on the bottom doesn't it seem like we than would have 500 gallons weighing down on it? It seems to me that it would take much more force to pump that 1 gallon from the bottom. Hmm

phinds

Gold Member
Suppose you have a straw two feet long and you stick it 1.5' into a very tall glass and suck up the liquid in the glass. That takes a certain amount of force. Now stick the same straw 1.5' into a lake and suck up the lake water. I think you logic would say that the latter requires more effort but of course it doesn't. What matters is the column of water being moved.

RipleyGallegos

Suppose you have a straw two feet long and you stick it 1.5' into a very tall glass and suck up the liquid in the glass. That takes a certain amount of force. Now stick the same straw 1.5' into a lake and suck up the lake water. I think you logic would say that the latter requires more effort but of course it doesn't. What matters is the column of water being moved.
Wow that's a really great way of putting it! But do you think sucking or pumping up is equivalent to pushing or lifting up?

phinds

Gold Member
Wow that's a really great way of putting it! But do you think sucking or pumping up is equivalent to pushing or lifting up?
Yes, if you are talking about exerting a force on a specific column of liquid. Again, all that matters is the amount of liquid being moved. If you are pushing up a 1cm diameter column of water it makes no difference whether that column is surrounded by a glass full of water or an ocean full of water.

RipleyGallegos

Yes, if you are talking about exerting a force on a specific column of liquid. Again, all that matters is the amount of liquid being moved. If you are pushing up a 1cm diameter column of water it makes no difference whether that column is surrounded by a glass full of water or an ocean full of water.
Thank you very much phinds!

"If this hand water pump was instead at the bottom of a well..."

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