# Can weight=atmospheric pressure*mass

• masti6
In summary,As w=force*mass.. but we can use atmospheric pressure instead of gravitational force because as per the law of gravity,the force exerted between the body are equal in magnitude. so the when atmospheric pressure is exerted on body the body will also exert same force to atmosphere. Thus, can w=atmospheric pressure*mass? Newton's 3rd law tells us that the force exerted by the air on a body is equal and opposite to the force exerted by the body on the air. But this has nothing to do with the weight of the body, which is the gravitational force exerted by the Earth on the body.

#### masti6

As w=force*mass..
but we can use atmospheric pressure instead of gravitational force because as per the law of gravity,the force exerted between the body are equal in magnitude. so the when atmospheric pressure is exerted on body the body will also exert same force to atmosphere
thus,
can w=atmospheric pressure*mass??

Newton's 3rd law tells us that the force exerted by the air on a body is equal and opposite to the force exerted by the body on the air. But this has nothing to do with the weight of the body, which is the gravitational force exerted by the Earth on the body.

masti6 said:
can w=atmospheric pressure*mass??
Note that the units do not match, so this equation is not physically meaningful.

masti6 said:
As w=force*mass..
but we can use atmospheric pressure instead of gravitational force because as per the law of gravity,the force exerted between the body are equal in magnitude. so the when atmospheric pressure is exerted on body the body will also exert same force to atmosphere
thus,
can w=atmospheric pressure*mass??

I often work in ultra-high vacuum chambers. If you are correct, stuff should start "floating" in those chambers because the atmospheric pressure is almost nil, causing it to have no weight.

Now do you think this actually happen?

Zz.

welcome to pf!

hi masti6! welcome to pf!
masti6 said:
… when atmospheric pressure is exerted on body the body will also exert same force to atmosphere

yes, the force of the body on the atmosphere is equal (and opposite) to the force of the atmosphere on the body

if you have a cube, the atmospheric pressure on the four sides will be equal to each other, and they will cannel out

however, the atmospheric pressure on the bottom will be slightly more than the atmospheric pressure on the top, by an amount density*height*g upward

so this will also be the net force exerted by the cube downward on the atmosphere (if there is atmosphere under the cube, and not something solid)
can w=atmospheric pressure*mass??

no, not unless the atmosphere is so thick that the body can float in it (eg on Jupiter)

if the cube is resting on the ground, the force on the ground will be the weight w (= mg) minus the "buoyancy" force density*height*g

Yes, it is possible to represent weight as the product of atmospheric pressure and mass. However, it is important to note that weight is typically defined as the force exerted on an object due to gravity. While atmospheric pressure does play a role in this force, it is not the only factor. Therefore, it may not be accurate to equate weight with just atmospheric pressure multiplied by mass. Additionally, it is important to consider the specific context in which this equation is being used and whether it is appropriate for the situation.

## 1. Is weight directly proportional to atmospheric pressure and mass?

Yes, weight is directly proportional to atmospheric pressure and mass according to the formula W = P x m, where W is weight, P is atmospheric pressure, and m is mass.

## 2. How does changing atmospheric pressure affect weight?

Changing atmospheric pressure can affect weight by either increasing or decreasing it, depending on the direction of change. For example, if atmospheric pressure decreases, weight will also decrease, and vice versa.

## 3. Can weight equal atmospheric pressure multiplied by mass?

Yes, weight can equal atmospheric pressure multiplied by mass, as long as the proper units are used. Atmospheric pressure is typically measured in Pascals (Pa) and mass in kilograms (kg), so the resulting unit for weight would be Newtons (N).

## 4. Is there a limit to the relationship between weight, atmospheric pressure, and mass?

Yes, there is a limit to the relationship between weight, atmospheric pressure, and mass. This is because the formula W = P x m assumes that the mass is constant, and atmospheric pressure is not the only factor that affects weight. Gravity, for example, also plays a significant role in determining weight.

## 5. Does altitude affect the relationship between weight, atmospheric pressure, and mass?

Yes, altitude can affect the relationship between weight, atmospheric pressure, and mass. As altitude increases, atmospheric pressure decreases, which can result in a decrease in weight. This is because there is less air pushing down on an object at higher altitudes, leading to a lower atmospheric pressure.