# Gauge pressure and atmospheric pressure

• ppppparker
In summary: But I'm going to assume that it does mean the gauge pressure of the water at the objects. How about you just go ahead and give us the answer, so that we can skip the discussion of the various definitions?In summary, the question asks for the gauge pressure of object B, given that it is submerged at the same depth as object A (1m) in a liquid with specific gravity of 0.877, and that the density of object B is one third that of object A. The gauge pressure of object A is given as 3atm. The equation for gauge pressure is p_gauge = P - P_atm. The question may be confusing because gauge pressure is usually associated with pressure gauges, but in
ppppparker

## Homework Statement

Objects A and B are submerged at depth of 1m in a liquid with specific gravity of 0.877. Given that density of object B is one third that of object A and that the gauge pressure of object A is 3atm, what is the gauge pressure of object B? (assume atmos pres is 1 atm and that g = 9.8m/s^2

## Homework Equations

p_gauge = P - P_atm

## The Attempt at a Solution

[/B]
I think I do understand gauge pressure, that it is a difference in pressures. Specifically the diff between atmospheric pressure and the pressure in the container. But I think of gauge pressure always in terms of a tire. Thats what's confusing me. Is the question saying that the objects have enclosed air that is at a certain pressure? I have the answer but failing to put the concepts together, please help thanks

ppppparker said:

## Homework Statement

Objects A and B are submerged at depth of 1m in a liquid with specific gravity of 0.877. Given that density of object B is one third that of object A and that the gauge pressure of object A is 3atm, what is the gauge pressure of object B? (assume atmos pres is 1 atm and that g = 9.8m/s^2

## Homework Equations

p_gauge = P - P_atm

## The Attempt at a Solution

[/B]
I think I do understand gauge pressure, that it is a difference in pressures. Specifically the diff between atmospheric pressure and the pressure in the container. But I think of gauge pressure always in terms of a tire. Thats what's confusing me. Is the question saying that the objects have enclosed air that is at a certain pressure? I have the answer but failing to put the concepts together, please help thanks
Gauge pressure normally means that when the pressure gauge reads zero, there is still atmospheric pressure present. Absolute pressure, on the other hand, means that the pressure scale reads zero when there is a perfect vacuum present. Atmospheric pressure has a non-zero reading, like 14.7 psi or 101.325 kPa, on the absolute pressure scale.

Still, given the particulars of the problem statement, since the two objects are submerged to the same depth in the same liquid, what does this tell you about the pressure of object B, given the pressure of object A?

The wording is indeed strange. Since you know nothing else about the objects, it is curious to speak of the gauge pressure of the objects. Surely it means the gauge pressure on, or at, the objects?

## 1. What is gauge pressure?

Gauge pressure is the pressure measured relative to atmospheric pressure. It is the difference between the total pressure and the atmospheric pressure at a given location.

## 2. How is gauge pressure different from absolute pressure?

Gauge pressure uses atmospheric pressure as a reference point, while absolute pressure is measured relative to a perfect vacuum. Absolute pressure will always be higher than gauge pressure because it includes the pressure of the atmosphere.

## 3. How is atmospheric pressure measured?

Atmospheric pressure is typically measured using a barometer, which measures the weight of the column of air above the instrument. It is commonly expressed in units of millibars or inches of mercury.

## 4. What is the relationship between gauge pressure and depth in a liquid?

The pressure at a certain depth in a liquid is directly proportional to the density of the liquid and the depth. This means that the deeper you go in a liquid, the higher the gauge pressure will be.

## 5. How does atmospheric pressure affect weather patterns?

Changes in atmospheric pressure can indicate the movement of air masses and can influence weather patterns. High pressure systems tend to bring clear skies and fair weather, while low pressure systems can bring clouds and precipitation.

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