Question regarding pressure and energy

In summary: Pressure has units of energy per unit volume and can be thought of in that way.But Watts are power, not energy. Energy is static, whereas power is rate of energy generation. So no, you can't take a static form of energy and have it continuously output power. It needs to be changing.
  • #1
GabrielLight
3
0
I'm referring to pressure as in atm, pascals and PSI, and energy as in joules or watts.

Can pressure be converted to energy in some way? I'm aware of the existence of "pressure energy", which is joules per volume, but it's not what I mean.

For example, if a pressure of 100,000 atm is exerted on a man with a surface area of 1.8m², could we somehow translate the pressure to watts/m², without violating fluid dynamics? Or are pressure and energy not related in this form?

Thanks in advance.
 
Physics news on Phys.org
  • #2
Pressure and energy are dimensionally different, so there is certainly no conversion from one to the other.
(You mention Watts, but that is a unit of power, which is different again.)
To get an energy from a pressure you need, in effect, a volume to multiply it by. That arises directly in the gas laws, e.g. pV constant at constant temperature. In Bernoulli's equation for incompressible flow we also find a p/ρ term, which we can think of as an energy per unit mass which somehow results from the pressure, p.

Can you explain more why you ask, or why you feel it should be possible?
 
  • #3
If you apply a force in a body of volume V, in its area surface A, the body experiences a pressure P=F.A that acts in it in order to peform one or more of this actions, such as a. expanding, b.contracting, c. deforming, d.heating, etc. In all cases, the P.V = W, that is the work done on the body. Knowing that W = K - Ko, you can see this relation. The pressure of a certain volume hot steam in a piston is the source of generating kinetic motion...you can also use the steam to rotate the stems of a mill, etc.
 
  • #4
GabrielLight said:
I'm referring to pressure as in atm, pascals and PSI, and energy as in joules or watts.

Can pressure be converted to energy in some way? I'm aware of the existence of "pressure energy", which is joules per volume, but it's not what I mean.

For example, if a pressure of 100,000 atm is exerted on a man with a surface area of 1.8m², could we somehow translate the pressure to watts/m², without violating fluid dynamics? Or are pressure and energy not related in this form?

Thanks in advance.
I'm surprised this didn't get a more direct response:

Pressure has units of energy per unit volume and can be thought of in that way. But Watts are power, not energy. Energy is static, whereas power is rate of energy generation. So no, you can't take a static form of energy and have it continuously output power. It needs to be changing.
 
  • #5
haruspex said:
Pressure and energy are dimensionally different, so there is certainly no conversion from one to the other.
Actually, pressure has units of energy per unit volume, which makes it useful in situations such as Bernoulli's equation.
 
  • #6
Lukeblackhill said:
the P.V = W, that is the work done on the body
Not quite. The work done is P.dV, i.e. there has to be a change in volume.
russ_watters said:
But Watts are power, not energy.
I did point that out in post #2.
russ_watters said:
Actually, pressure has units of energy per unit volume, which makes it useful in situations such as Bernoulli's equation.
That does not contradict what I wrote. It still leaves pressure and energy dimensionally different, just as energy and power are dimensionally different. In the one case the ratio is a volume, in other, time.

The OP explicitly stated that a direct conversion was sought, not pressure as energy per volume.
 

1. What is pressure and how is it related to energy?

Pressure is the force per unit area applied to an object or substance. It is related to energy through the concept of work, which is the product of force and distance. When a force is applied to a surface, it does work by transferring energy to the object, resulting in a change in pressure.

2. What is the difference between pressure and energy?

Pressure and energy are related but are two different physical quantities. Pressure is a measure of force per unit area, while energy is the ability to do work. Pressure can be thought of as a measure of how concentrated a force is, while energy is a measure of the amount of work that can be done by a force.

3. How does pressure affect energy in a system?

The presence of pressure in a system can affect the amount of energy that is present and can also influence the way energy is transferred within the system. For example, high pressure can increase the amount of energy in a gas, and the release of pressure can result in a release of energy in the form of an explosion.

4. Can pressure be converted into energy?

Pressure can be converted into energy through processes such as compression, where work is done to increase the pressure of a gas, resulting in an increase in the gas's internal energy. Pressure can also be converted into other forms of energy, such as electrical energy through piezoelectricity.

5. How does pressure affect the behavior of matter?

Pressure plays a crucial role in the behavior of matter. It can affect the density, volume, and phase of a substance. For example, increasing the pressure on a gas can cause it to condense into a liquid. Pressure can also influence the properties of materials, such as their strength and elasticity.

Similar threads

Replies
15
Views
2K
Replies
13
Views
20K
Replies
1
Views
997
Replies
1
Views
2K
Replies
5
Views
1K
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
3
Views
1K
  • Mechanics
Replies
12
Views
2K
Replies
18
Views
1K
Back
Top