Opted Physics question #13

[biologyguy]

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Atmospheric pressure is very nearly 100 kPa. A sealed container of air at 1 atmospheric pressure has a door 1 m wide and 2 m high. This door is very hard to open during HIGH pressure days. If the atmospheric pressure on
the outside of the container is just 1 percent greater than on the inside, then what added force in Newtons is required to open the container door?

How do I do this?

 

[DaveSch]

Pressure = Force / Area so F = P*A

The area of the door is 2, the pressure inside is 100 kPa, outside is 101 kPa. F = (101 - 100) * 2

Hope that helps!

 

[Commando303]

OK, I don't remember ever learning anything remotely related to this...

 

[EyEnStein 07]

OK, I don't remember ever learning anything remotely related to this...

This should have been covered in your first semester physics course under the topic of Fluid Mechanics. This should have been the "basic" stuff you learned first.

 

[Commando303]

From Physics, I, all I really recall is mechanics/kinematics, energy (including "work"), and rotational motion. I think we never made it to waves, sounds, or fluids — if this would have been mentioned during "fluids," I suppose I know why it looks foreign, to me.

 

[EyEnStein 07]

yeah, maybe your class was a bit slow. I took the calc based and we got through all the way a little past fluids but right before waves. A lot to cover, but yeah too bad however its not too much to remember just a few things that might help.

 

[Commando303]

What persuaded you to take the calculus-, rather than algebra-based, version of the course? As far as I know, most "medicine-minded" students opt for the latter.

 

[EyEnStein 07]

What persuaded you to take the calculus-, rather than algebra-based, version of the course? As far as I know, most "medicine-minded" students opt for the latter.

because i might want to be a physics/math major...and i already took an algebra based physics in a community college through my high school. What would be the fun in a repeat?

One concern i do have is that in the Algebra based classes i got A's in both, however i didnt do so well in calc based (this is not because i didnt understand it, i had a lot on my mind and going through stuff my freshman year) so i hope everything gets considered in my GPA when i apply to optometry school. I am in Elec.&Mag. now and doing much better.

 

[Commando303]

Ugh — I hated electricity and magnetism! Optics and (special) relativity, however, were pretty damned interesting.

 

[EyEnStein 07]

electricity is not that bad...too much integration though. However i do hear magnetism is not fun at all. Optics i like (which is why im considering O.D/PhD if i can make it there). I just worry a bit about the OAT physics lol, because the calculations are really easy, concepts are very basic and all i have been doing since my physics 1 class is loads of calculations that require a lot of thinking and strong math skills.