The CF and Physics

[fleeingjam]

Hi, i have to do this project in physics on things that friction to operate, now my physics teacher hates it when i incorporate things with the CF which has made me want to do it more, so can anyone tell me any thing in the CF that uses friction as an advantage or disadvantage or simply to operate or function.

Your input would be greatky appreciated
-Usman Syed

 

[Michael Dorosh]

Paper, Sand, Wet or Dry, 220 Grit, Soldiers, For The Use Of.

 

[rw4th]

Maybe you could explain a bullet's spin, or how you get ass-rash when you've marching for too long  ;D

 

[Pieman]

How about describing the frictional air resistance in projectile motion. Like on the shell of a artillery gun.

You can explain how because of air friction, the motion of the shell is no longer the standard projectile trajectory but it altered, usually in  a non-linear manner, especially if you encounter different air densities.

How is your calculus? You can wow your teacher with this one if you know a little. Either way,  PM me if you would like a little help with this.

 

[Michael OLeary]

Air resistance on projectile motion is more an example of friction working against the military efort.

A simpler example you might want to consider is the friction between the rope and rapeller as a function of length of rope in contact as the braking arm moves in an arc to control descent speed.

 

[FormerEnlisted]

just drop the course then tell him it was because you joined the CF, solves both problems at once... ^-^

 

[dutchie]

I know your kidding QOR, but he should definately NOT quit the course.

The only other one I could think of is related to Pieman's suggestion. My 1st year Physics prof actually used this example:

If you fire a rifle on a perfectly flat trajectory, over completely flat ground, and dropped bullet #2 from you your hand at the moment that bullet #1 left the barrel, they both would strike the ground at the same time. It doesn't matter how fast the bullet travels in the 'y' direction, they both still falls at 9.18 m/sec2   in the 'x' direction (I think that's the formula - been a while   ). This is true barring wind resistance, of course, but perhaps you could calculate how wind resistance (maybe even at different temps!) would change this?

Air resistance on projectile motion is more an example of friction working against the military efort.

true, but he asked for advantages and disadvantages:

....friction as an advantage or disadvantage....

 

[Duotone81]

Caesar, You mean 9.81m/sec2 in the Y direction . The X axis typically runs parallel to the ground in these types of questions.

Usman_Syed, an example that comes to mind is the bridges that the Engineers construct for mobility. Their must be sufficient frictional force between support columns and girders/beams in order for the bridge to not collapse. That is why bolts must be tightened to the minimum specified torque on these sorts of structures. They ensure that their is sufficient frictional force between structural members.

 

[fleeingjam]

OMG, You guys are awsome my teacher will court martial me for sure Um I was lookin more on the line of sorta like kinetic and static frictiion but i think all the examples are great. Go CF Go

 

[Pieman]

It doesn't matter how fast the bullet travels in the 'y' direction, they both still falls at 9.18 m/sec2   in the 'x' direction (I think that's the formula - been a while   ). This is true barring wind resistance, of course, but perhaps you could calculate how wind resistance (maybe even at different temps!) would change this?

Air resistance will have an effect, and the temperature changes the density of the air so there is an effect. Depending on the situation it can be quite a lot.  It can be calculated using very much the same methods as the problem I mentioned, but if one does not know some basic calculus, it would be kind of difficult to solve....with any remote sense of accuarcy that is.

Um I was loolookingre on the line of sorta like kinetic and static frifrictiont i think all the examples are great

Air resistance is an example of kinetic friction.

A simpler example you might want to consider is the friction between the rope and rapeller as a function of length of rope in contact as the braking arm moves in an arc to control descent speed.

Zzzzzzzzz.... Ropes, pulleys, ramps...anyone who takes physics is going to see lots and lots of those problem sets. Too many problems are geared towards engineers. But actually it is not a bad friction example because it is a easy way to show conservation of energy. The rapeller at the top of a drop has a specific amount of potential energy, while traveling down, some of that is transfered to the velocity of the falling person. By using the friction of the braking, the energy in the decent is converted to thermal energy through friction. Showing conservation of Energy in a problems is always a good thing.