Why does hydrostatic pressure drop and some momentum question?

[scilearner]

Hello everyone,

 

If there is a pipe and it has a certain hydrostatic pressure and then goes through a region of high resistance. Why does the pressure drop? If hydrostatic pressure is due to gravity. Gravity is always there right?

 

Momentum,

So in the pipe when the molecules are moving. The hydrostatic pressure is converted to kinetic energy. Hydrostatic pressure molecule, hits another molecules and it goes flying, while reducing the pressure of the hydrostatic molecule. My question is can't the molecules that are moving (kinetic energy) collide and give back the lost hydrostatic energy?

 

Thanks

[swansont]

Hello everyone,

 

If there is a pipe and it has a certain hydrostatic pressure and then goes through a region of high resistance. Why does the pressure drop? If hydrostatic pressure is due to gravity. Gravity is always there right?

 

Where else is the energy going to come from that is lost to the resistance?

 

 

Momentum,

So in the pipe when the molecules are moving. The hydrostatic pressure is converted to kinetic energy. Hydrostatic pressure molecule, hits another molecules and it goes flying, while reducing the pressure of the hydrostatic molecule. My question is can't the molecules that are moving (kinetic energy) collide and give back the lost hydrostatic energy?

 

Thanks

 

It really doesn't make sense to discuss the pressure of a single molecule.

 

However, perhaps this will help: there is motion of the individual molecules, and there is motion of the center-of-mass of some collection of molecules. It may help to think about those separately.

[scilearner]

Where else is the energy going to come from that is lost to the resistance?

 

 

 

 

It really doesn't make sense to discuss the pressure of a single molecule.

 

However, perhaps this will help: there is motion of the individual molecules, and there is motion of the center-of-mass of some collection of molecules. It may help to think about those separately.

 

Thanks swansoft for the help For the first question what I mean is even if pressure drops to zero gravity would give some energy again, the force is always acting. For the second one ok if a collection of molecules (A) hit another collection of molecules(B) and make them move along the pipe. A would have less energy, I consider A as the molecules providing hydrostatic pressure, so if that drops what happens B(kinetic energy molecules) hit A can it gain hydrostatic energy again. Thanks