four forces

jjj · Post by **jjj** » Fri Aug 18, 2006 1:10 am

It's sometimes tough to discuss a topic like this on a forum because when we try to be brief our ideas often get distorted. I agree that some terms and conventions are interchageable and therfore our message can be lost when we get into detail. One thing I do know for sure is that I'm shit-faced and it's time for bed and I'm also glad that BEECHY chimed in because he's a fucking idiot and next to him we all look like Newton.

The Earth is flat - time is flexible - coriolis is an effect not a Force - it's all just a matter of perspective - perhaps one more drink B4 bed - I hope at least that BEECHY is getting some pussy.

jjj

Aeros · Post by **Aeros** » Fri Aug 18, 2006 4:21 am

kavupilot wrote:Weight is a force, and is measured in pounds, newtons, etc according to grimey...i thought by reading this that finally everybody had finally figured it out........grimey weight is not measured in pounds...maybe you are thinking of slugs? an english unit

Pounds cut both ways -- lbm is pounds (mass), lbf is pounds (force).

1 lbm is NOT the same as 1 lbf.

Slugs are a unit of mass. If you refer to the mass of an object in slugs it simply makes the math simplier when working in the Imperial system.

niss · Post by **niss** » Fri Aug 18, 2006 4:52 am

I realize you're a student, but a piece of advice, do your homework before you give out any lessons

As for the question,

Weight is a force, and that force is a vector quantity having both a magnitude and a direction associated with it.

When you lift say a ball 1m off the ground you are building up potential energy, this energy build up is caused by the gravity and not the weight, If the gravity was absent the ball would have no weight.

For instance, a sattelite orbiting the earth, all would agree that its weightless and an astronaut working on it would also agree as he is floating around in space with it. However that same sattelite is trapped in the earths oribt and subject to the force of gravity while not having weight.

JigglyBus · Post by **JigglyBus** » Fri Aug 18, 2006 7:17 am

Lots of backyard scholars out today.

The latest Scientist to grace our forum is Professor Niss.

Why don't people recheck their 'opinions' before they post them, in an attempt to sound like an authority.?????

..."For instance, a sattelite orbiting the earth, all would agree that its weightless and an astronaut working on it would also agree as he is floating around in space with it. However that same sattelite is trapped in the earths oribt and subject to the force of gravity while not having weight.""

All would agree???? Is that all the Niss family, or all of the people in your kitchen?? I for one, do not agree.

Funny thing is, you even contradict yourself in the same sentence. You know that the satellite has mass, you state that it's subject to the force of gravity, and then you say it has no weight.

Think that one through again.

Or, better yet, please look it up.

niss · Post by **niss** » Fri Aug 18, 2006 7:27 am

So items in space are not weightless?

JigglyBus · Post by **JigglyBus** » Fri Aug 18, 2006 7:38 am

You have the internet, don't ask me, look it up for yourself.

niss · Post by **niss** » Fri Aug 18, 2006 7:46 am

http://science.howstuffworks.com/weightlessness1.htm

Weightlessness is more correctly termed microgravity. You are not actually weightless, because the Earth's gravity is holding you and everything in the shuttle in orbit. You are actually in a state of free-fall, much like jumping from an airplane except that you are moving so fast horizontally (5 miles per second or 8 kilometers per second) that, as you fall, you never touch the ground because the Earth curves away from you. It's like this: When you stand on a bathroom scale, it measures your weight because gravity pulls down on you and the scale. Because the scale is resting on the ground, it pushes up on you with an equal force -- this equal force is your weight. However, if you were to jump off a cliff while standing on a bathroom scale, both you and the scale would be pulled down equally by gravity. You would not push on the scale and it would not push back against you. Therefore, your weight would read zero.

Weight is relative to the force of gravity pulling an object. Twice the gravity twice the weight. Half the gravity half the weight.......gravity is keeping objects in space in orbit but they are not pulled onto a stationary object theirfor no weight....

beechy · Post by **beechy** » Fri Aug 18, 2006 7:51 am

Yeah i had a brain slip there....my apologies.....However most of what i said is true.

JigglyBus · Post by **JigglyBus** » Fri Aug 18, 2006 7:55 am

Niss, buddy, you're taking you incomprehension to new levels with that last post.

You quote this "You are not actually weightless" and then you go on to say that you are infact weightless.

Read that same quote a few more times, and discover that it clearly states that you DO have weight in space, or jumping of a cliff for that matter.

You know the formula as a million people have posted it here. Are you planning on rewriting the foundations of physics?

niss · Post by **niss** » Fri Aug 18, 2006 8:04 am

No, However, weight is relative, as shown in differant gravatational environments. So I would argue that gravity is infact the dominant if not actual force affecting an aircraft.

cone · Post by **cone** » Fri Aug 18, 2006 8:14 am

I think anyone who has read this forum is now dumber for having done so.

I can't even bring myself to respond

grimey · Post by **grimey** » Fri Aug 18, 2006 8:16 am

niss wrote:theirfor no weight....

No (well, really, little) APPARENT weight. The object is still being affected by forces, as it's in an orbit. Newton's laws of motion, it would travel in a straight line if it were not. It simply isn't subject to a significant force from its immediate surroundings. So yes, in the vomit comet, you feel weightless, but only because everything around you is also accelerating with the same vector, and the gravitational force exerted by the plane on your body is minimal. You're not truly weightless however, if you were you wouldn't be accelerating.

grimey · Post by **grimey** » Fri Aug 18, 2006 8:25 am

Anyone else get the feeling that anyone from the flying public who might be reading this is now terrified of flying?

beechy · Post by **beechy** » Fri Aug 18, 2006 8:45 am

Understanding gravity really isn't crutial to flying. however, what concerns me is the amount of people on this forum who are willing to castrate someone for having a small brain fart. that is the real reason someone should be affraid of flying from reading this forum.

Does not one of you make mistakes? you probably wouldn't know if you did because you are too bus admiring yourselfs and telling yourself what a good pilot/perfect human you are. You are the danger to passangers. Mistakes don't kill people, not recognizing a mistake or not allowing yourself to admit mistakes is what kills passangers.

Hedley · Post by **Hedley** » Fri Aug 18, 2006 9:30 am

Gravity itself is an acceleration resulting from the spinning of the earth

You just can't buy entertainment like this ... keep those gems coming!

Understanding gravity really isn't crutial (sp) to flying

Oh my god ... I haven't laughed this hard in years! Ever considered doing stand-up comedy? Garth Wallace, look out! Beechy has arrived!

beechy · Post by **beechy** » Fri Aug 18, 2006 9:38 am

Hey headley, you'll be laughing on the otherside of your face when you have a mid-air from not using your radio while doing low level aerobatics!!

Oh and so you know spinning does have an affect on local gravities, hence the equatorial bulge. So it lessens it, people make mistakes....and you're still a dink. Go admire youself some more.....

physicsbuff · Post by **physicsbuff** » Fri Aug 18, 2006 9:46 am

C-HRIS wrote:
You postulated that Weight = Mass x Gravity. I would appreciate if you could provide a reference for this.
Grade 11 Physics/common knowledge could be considered your reference

This brings up a few questions:

If weight is in Kilograms and Mass is in Kilograms which I multiply by a constant with the units of meters per second squared - how can I possibly get a result of my weight on Earth in Kilograms.

Weight is not measured in kilograms, but rather Mass is measured in kilograms and weight is the force due to gravity. Its units are kgm/s^2 or Newtons. It is a vector force (therein having both magnitude AND direction towards the center of the body exerting said gravitational force) which varies depending on your location on Earth, (ie: distance from the equator). It is correct to say one "weighs" less on the moon since the acceleration due to gravity is LESS than on earth, while your mass remains the same.

This brings up another fun point of discussion that touches on relativity and objects in motion - consider a closed system - me sitting here in front of my computer where I'm at rest and not falling - I therefore have no acceleration - therefore I have no weight according to your formula - yet the scale tells me different. How do you explain that?

And that does not touch on relativity in any serious way. Perhaps you mean it deals with inertial frames of reference for I did not see you use E=mc^2 in any way, shape or form. Why don't you all stick to flying and leave the Physics about it to us, you're thinking too hard and it's painful to read this jibba jabba.

anyone feel free to correct me - my last Physics class was 12 years ago.

Obviously.

grimey · Post by **grimey** » Fri Aug 18, 2006 9:47 am

beechy wrote:Hey headley, you'll be laughing on the otherside of your face when you have a mid-air from not using your radio while doing low level aerobatics!!

Oh and so you know spinning does have an affect on local gravities, hence the equatorial bulge. So it lessens it, people make mistakes....and you're still a dink. Go admire youself some more.....

The bulge has an effect on local gravity, but only because you're further from the center of mass of the earth. The spinning causes the bulge, but the spinning itself has nothing to do with the gravitational forces felt. If the earth didn't bulge, if it were perfectly rigid, there'd be no significant difference in the forces.

Hedley · Post by **Hedley** » Fri Aug 18, 2006 11:14 am

I suppose a lack of concern about gravity would explain why somone would perform minimal engine maintenance ...

superiorwhore · Post by **superiorwhore** » Fri Aug 18, 2006 11:57 am

physicsbuff wrote:C-HRIS wrote:
You postulated that Weight = Mass x Gravity. I would appreciate if you could provide a reference for this.
Grade 11 Physics/common knowledge could be considered your reference

This brings up a few questions:

If weight is in Kilograms and Mass is in Kilograms which I multiply by a constant with the units of meters per second squared - how can I possibly get a result of my weight on Earth in Kilograms.

Weight is not measured in kilograms, but rather Mass is measured in kilograms and weight is the force due to gravity. Its units are kgm/s^2 or Newtons. It is a vector force (therein having both magnitude AND direction towards the center of the body exerting said gravitational force) which varies depending on your location on Earth, (ie: distance from the equator). It is correct to say one "weighs" less on the moon since the acceleration due to gravity is LESS than on earth, while your mass remains the same.

This brings up another fun point of discussion that touches on relativity and objects in motion - consider a closed system - me sitting here in front of my computer where I'm at rest and not falling - I therefore have no acceleration - therefore I have no weight according to your formula - yet the scale tells me different. How do you explain that?

And that does not touch on relativity in any serious way. Perhaps you mean it deals with inertial frames of reference for I did not see you use E=mc^2 in any way, shape or form. Why don't you all stick to flying and leave the Physics about it to us, you're thinking too hard and it's painful to read this jibba jabba.

anyone feel free to correct me - my last Physics class was 12 years ago.

Obviously.

Blah Blah Blah,
Nice first post you come in here trying to teach us all a lesson and make us feel dumb, well than fluffer, ohh sorry buff.
so if newtons kgm/s^2 why can the Star Trek Enterprise travel at ludicrous speed?

mellow_pilot · Post by **mellow_pilot** » Fri Aug 18, 2006 1:52 pm

That's star SHIP enterprise. Dumbass

grimey · Post by **grimey** » Fri Aug 18, 2006 1:56 pm

mellow_pilot wrote:That's star SHIP enterprise. Dumbass

Nah, it's Spaceballs. Trekkies arn't dumb enough to go to ludicrous speed, it's too dangerous. And tacky... ugh, plaid.

niss · Post by **niss** » Fri Aug 18, 2006 2:22 pm

Speaking of all things scottish.....do scotts like their sheep shaved?

jjj · Post by **jjj** » Fri Aug 18, 2006 2:38 pm

It's a good thing you showed up Physics buff,

"Relativity" is an all encompassing term which covers in the very least: General, Special, and Galilean relativity.

Inertial frames of reference falls in nicely with the term of relativity so I made no error there. In fact the term was explicitly discussed by Galileo a few hundred years before Einstein was born. Since I'm not concerned with what happens to my mass as I approach the speed of light - you can take your E=mc squared and ram it.

jjj

. ._ · Post by **. ._** » Fri Aug 18, 2006 2:45 pm

I thought the four forces were

EARTH WIND AND FIRE!!!!

And of course- SOUL, brother! That's how a funky cat really flies!

-istp

four forces

Four forces

Re: Four forces