Kenteth

And I failed highschool phsyics!

Kenteth

Pressure is measured in mass per square inch, in terms of weight

Volume would be considered per cubic inch in terms of mass.

BTW

Weight = Mass × Gravity


You are welcome to tell me that air doesn't weigh anything, or has no mass... but... well... nevermind.

Let me say this, if air didn't weigh anything, I would be 25 feet tall and only weigh 135 lbs!!! But instead im 5"10 and 135lb. Thats because of the lb/PSI that is pushing down on me right now.

In space their is a vaccum (void of mass, and hence gravity). Be my guest to try to start your rex in space, but it won't happen without o2 supply.

o2 weighs alot. Ask any sea diver. A empty tank will weigh considerbly less than a full tank!

Kenteth

i need to shutup and go outside now.

Pyrocloud

Ahha!

NZConvertible

Kenteth, thanks for the physics lesson, but I knew all that.
I was pointing out that psi is a unit of pressure, not weight. The two cannot use the same unit, because they are completely different.
However...
That's not quite correct. Pressure is force per unit area, not mass per unit area. Mass and weight/force are often confused, but again they are completely different.
Mass is the physical amount of substance an object contains. Weight is the force that mass applies to whatever it's resting on at a particular gravitational pull.
On the moon for example, where the gravitational pull is much less than on Earth (~1/6), an object will weigh much less but its mass will be unchanged.

Kenteth

Thanks for the correction Its been awhile. I did bring a curious note though-- does pressure of air change depending on altitude. I'm not sure that it would be much noticeable, but mainly curious. Up north we have to adjust cooking times when baking because of the elevation. Anything similar?

Kenteth

I suppose one of us could pull of the equation for o2 density versus altitude and actually find the formula for air psi to altitude at a constant 10lb psi @ sea level.

NZConvertible

Absolutely. As altitude increases, the air gets thinner and thinner until there's none left (we call that space), so the air pressure also decreases.
At sea level air pressure is 14.7psi, at 5000 feet it's 12.2psi, at 10000 feet it's 10.1psi and at 20000 feet it's 6.8psi.

Kenteth

useful information, thanks!!

HAILERS

****does pressure of air change depending on altitude*****


That's why we have a Atmospheric Pressure Sensor in/on the car. It's located on the passengers side of the crew compartment, above the feet to the right. Called the ATP in this schematic. Nobody ever mentions this device on this forum. I thought I'd be the first.

Kenteth

kudos