physics buff's opinions needed?

Question

We were haveing a disscussion in class today and I was wondering what you guys think of it
The debate was that what is the point of developing concepts that employ frictionless surfaces, ignore air resistance, ect. are bogus because they have no meaning in the real world; and therefore are of no use to us and instead of focusing on things like this we should be focusing on "real physics" instead

I was just wondering what everyones opinion was
thanks alot!

also, an in depth description of your opinion would be appreciated : )

Answer 1

It is real physics. You are isolating one phenomenon so you can analyze it. Sometimes you ignore things like air resistance because you know they won't affect your answer. Part of 'real world' physics is knowing when you can do this. If you're calculating a trajectory, you can ignore air resistance for a cannon ball but not a ping pong ball.

Sometimes you calculate in stages. First, calculate the trajectory ignoring friction. Then calculate the effect of friction at those velocities. If the effect is small, you can make a small adjustment to your results. If not, then you need to do a more complex calculation. Then, you can compare the results from your complex calculations to the simple ones. If they are dramatically different, you may have made a mistake.

Sometimes all you need is a limit, so you calculate a final velocity without friction, and you know that your velocity will be less than that when you consider friction.

Sometimes getting a more accurate answer to a particular problem isn't the best use of your time.

Answer 2

Because you can't handle the math. Anything that involves friction or drag requires use of partial differential equations (PDEs).

Nonetheless, the idealized equations approximate the real physics well enough that many of the ad hoc solutions to real problems are based on "corrections" to the idealized solutions, rather than on the actual PDE, since most of the PDEs can't be solved in closed form and require iterated numerical solutions.

As an example, while the real ballistics problems have to be numerically solved, the textbook parabolic equations come very close to the numerical solutions.

Answer 3

That strategy would pretty much put physics back into the mind set of the beginning of the 20th century when it was commonly thought that all that science had to offer had already been discovered.

Imagine if Einstein had adopted this line of reasoning.

I have to wonder what exactly was meant by "real physics." Perhaps "real physics" as apposed to theoretical physics? Certainly not Newtonian physics vs. relativity?

Research and discoveries that seem to have no
"meaning in the real world" have led to some pretty amazing stuff.

Answer 4

Well, first of all, these example situations are essential to begining study in physics- you have to walk before you can run. Also, you'll find that some of the situations occur more often than you'd think, for example, in the development of maglev trains in the future, if a vacuum is used, you have neither of the two forces you mentioned. In order to fully appreciate what air resistance and friction do, we must be able to understand what happens in their absence.

Answer 5

Condensate physics deal with condensates. These are supercooled materials that behave in bizzare ways. Superfluids have 0 viscocity. I'm not too familar with these but supersolids might show behavior of 0 friction.

http://en.wikipedia.org/wiki/Super_solid
http://en.wikipedia.org/wiki/Superfluid

I'm not sure how friction will fit here, but there are certainly materials that can ignore some resistances most other materials cannot.

Google condensate physics, bose-einstein condensates, superfluids...etc

Almost forgot the practical application of these is things like superconductor with 0 resistance. Room temperature superconductor, if it can be made, will save load of energy being trasmitted to places and help to create all kinds of cool inventions.

Answer 6

I think that it's still important to learn concepts in the "ideal environment" (no resistance) because that is the basis of the concept. Once that concept is understood, then you can start adding on top of the the much more complex calculations of friction and drag.

Analogy:
You have to understand the basics of how a car works: (gas, breaks, steering wheel, lights etc.) as your foundation before you can start to learn on how the more complex systems of the fuel injection, Anti-Lock breaks, Contour steering systems work.

Answer 7

The real world is chaotic, but linear formulas are easier to solve. Many problems are just not practical if you add in all the non-linearity of the situation. So, it is easier to model them in ideal situations with no turbulence, friction, or other factors. This allows you to see the concept more clearly before muddying it up, literally.

Answer 8

a million) speed could be 0 while some thing is accelerating, case in point, in case you throw a ball right away up interior the air. on the authentic of the balls path it could have a speed of 0 yet will nevertheless be accelerating. 2) the version between speed and velocity is that speed incorporates a path so the no. 3) definite, via fact the example above with the ball, yet you may could desire to advance up the ball on the comparable velocity as gravity for it to artwork as you asked. 4) No

Answer 9

Well through assumptions, we simplify problems and get close estimations. Without assumptions, problems can get so tough that they become unsolvable using known mathematical approaches and in the end nothing gets done. No rockets get built. No internet. No robots. No advanced equipment.